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JUN 2<' I9f6 

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It IS the purpose of this volume to present such 
material on physiology, hygiene, and sanitation as may 
be of practical service to young people. For this reason 
function is emphasized rather than structure, and the 
laws of health receive more attention than the mechan- 
ical operation of bone, muscle, gland, and tissue. 

In the earlier chapters of the book stress of teaching 
is laid on right habits of sitting, of standing, and of walk- 
ing; on the relation of the school desk to spinal curva- 
ture; on laws of growth and their relation to correct 
habits of posture; on the development of muscular vigor; 
and on the renewal of the tissues of the body. 

Attention is also called to the source of all muscular 
energy — the blood. Simple tests, easily applied, explain 
the cause of rapid and slow heartbeat and show how 
the power of the heart and of the lungs may be increased 
gradually. Reasons are given why the untrained heart 
should not be greatly taxed, and why extreme breath- 
lessness is objectionable. The effect of alcohol on the 
heart and on the arteries is made plain, and the effect 
of tobacco on the action of the heart is illustrated by 
means of the sphygmograph. 


Professor Chittenden's notable experiments with sol- 
diers in New Haven and Dr. Cannon's experiments 
with cats in the Harvard Medical School add a touch 
of picturesque reality to the otherwise prosaic subject 
of digestion. Through these experiments we are intro- 
duced to the change of food from solid to liquid in the 
alimentary canal, to the absorption of chyle by the villi, 
to the enrichment of the blood, and to the work of the 
liver and the kidneys in purifying the blood. 

The nervous system also is studied primarily from the 
point of view of function and of efficient service. The 
student learns how the body is controlled by laws of 
habit and by will power, how habits are formed, and 
how it comes to pass that a happy state of mind 
helps on the cause of good health. 

The present volume is, in some respects, a readjust- 
ment of The Body arid its Defenses. Certain subjects 
treated there have been pressed into smaller compass 
here; while certain other subjects touched upon there 
have . received more extended treatment here. To a 
large extent this new subject matter concerns itself with 
sanitation, hygiene, and the food requirements of the 
body. The following are a few of the new topics 
interspersed among the old: rules for right eating; 
balanced menus ; food for bulk ; food waste ; why we 
cook our food; pure-food laws, and food inspection; 
canned foods; patent medicines; mistakes in eating; 


auto-intoxication, how brought about, how avoided; 
headache and auto-intoxication; the relation of alco- 
hol to taxes, crime, and poverty ; treatment of the eyes ; 
hygiene of the ear. 

A new feature of this book is its chapter on sanitation, 
where contrasts are drawn between country conditions 
and city surroundings; between the solution of sanitary 
problems for congested cities and for scattered country 

Still another chapter shows how our common microbe 
diseases — measles, scarlet fever, malaria, smallpox, diph- 
theria, yellow fever, etc. — are passed about, and how 
we may escape them through vaccination, antitoxin, 
cleanliness, and general physical vigor secured through 
the observance of the laws of health. 

In this volume, as in The Body and its Defenses, 
tuberculosis is studied — its cause, its prevention, and 
its cure ; also typhoid fever as related to pure water and 
clean milk; also dangers from the public drinking cup 
and the public towel, from the fly, the mosquito, the 
hookworm, and the rat. 

These and other related topics have been brought to 
the notice of the students of this volume with the hope 
of imparting such enthusiasm for personal health and 
such clear notions of how to secure it that healthful 
habits may result; that the bodies of growing children 
may be strengthened as well as straightened ; that lives 


may thereby be lengthened ; and that through increased 
physical well-being the sum of human happiness may 
itself be increased. 

For the convenience alike of teacher and of pupil, side- 
headings serve as a ladder of connected topics through- 
out the book. A series of questions is also added to 
each chapter, and many illustrations reenforce the teach- 
ings of the text. Special mention should be made of 
indebtedness to the American Journal of Physiology 
for illustrations used by Dr. Cannon in his article on 
" The Movements of the Stomach studied by Means 
of the Rontgen Rays," and to Professor Chittenden for 
photographs of the soldiers with whom he carried on 
his food experiments. 

Other valuable illustrations have been reproduced 
from The Human Mechanism by Theodore Hough and 
W. T. Sedgwick, from Alcohol and the Human Body 
by Sir Victor Horsley and Mary D. Sturge, and from 
Unser Korper by F. A. Schmidt. To each of these and 
to many other important works this small volume is in- 
debted not merely for illustrations but also for valuable 
facts which have been used in the preparation of its 

subject matter. 

F. G. J. 



I. Changeless Records i 

Taking the Body's Record. When Cartilage turns to Bone. 
Making Our Own Records. How the Right Kind of Body 
Helps. Testing Yourself. The Correct Standing Position. The 
Correct Sitting Position. Lateral Curvature of the Spine. How 
to prevent Lateral Curvature. 

II. Muscles: what they Are and what they Do ... 13 

The Strong, Bent Back. Effect of Work on Stretched Muscle. 
To Balance Development. The Law of Muscle Change. One 
Way of Developing the Muscles. Antagonistic Muscles. Exer- 
cise without Apparatus. Studying Muscle Structure. Bundles 
of Fibers. Connective Tissue. Tendons. What makes Tough 
Muscles. Two Classes of Muscles. Weight of Muscles. 

III. Bones — the Framework of the Body 30 

Bones and Muscles. Bone Structure. Chemical Composition of 
Bones. Young and Old Bones. Shape and Size of Bones. The 
Spinal Column. Wedge-Shaped Vertebrae. Bones Enlarged 
by Work. The Foot under Pressure. The Bones of the Foot. 
Rules for Foot Hygiene. Joints and their Ligaments. The 
Hinge Joint A Ball-and-Socket Joint, The Synovial Fluid. 

IV. The Heart at Work 48 

The Pulse. The Pulse Beat and the Heart Beat. The Effect 
of Exercise on the Heart. What the Pulse Beat Proves. 
The Heart Muscle. Overtaxing the Heart. Training Heart and 
Muscles Together. Overstretching the Heart. Heart Develop- 
ment. Harvey's Discovery. Arterial and Venous Blood. Ar- 
teries and Veins. The Work of the Heart. The Use of 
Valves in the Veins. Experiments with the Blood Flow. 




The Structure of the Heart. The Double Work of the Heart 
Capillary Connections. The Circulatory System. Corpuscles 
in the Capillaries. The Blood Supply. Exercise and the 
Blood Supply. 

V. Nicotine and the Sphygmograph 73 

Tests with the Sphygmograph. General Effects of Smoking. 
Effect of Smoking on the Heart. The Tobacco Heart. How 
Nicotine gets to the Heart Effect of Nicotine on the Heart. 
Dr. Seaver's Tests. 

• VI. Blood and Lymph Inside and Outside the Tubes . 82 

Blood Examination. Coagulation. Blood under the Micro- 
scope. The Blood's Important Work. Exchanges along the 
Tubes. Gas Exchanges in the Blood. Lymph and Oxidation. 
The Lymphatic System. 


VII. Alcohol in the Blood Stream 

Slow Circulation of the Blood. Alcohol and the Heart Beat 
Testing the Heart Beat with the Sphygmograph. Alcohol 
and Heart Vigor. First Effects of Alcohol. The Real Harm 
of Alcohol. Fat about the Heart. Weakened Heart and 

VIII. Trained and Untrained Lungs 103 

What is Breathlessness.'^ The Cause of Breathlessness. Speed 
and Breathlessness. Tests of Chest Capacity. Increasing the 
Chest Girth. Structure of the Lungs. Work of the Lungs. 
Inactive Air Sacs. Health and Exercise. The Breathing 
Apparatus. Clean Air for the Lungs. Value of Moist Air. 
Getting an All-round Development 

IX. Eating and Our Food Supply .121 

Experiments in Eating. What Food does for the Body. The 
Five Food Substances. Studying the Cost of Foods. Plants 
as Food Producers. Carbohydrate for Energy. The Proteids. 
Proteid for Tissue Building. The Fats. The Minerals. Need 
of Drinking Water. Rules for Right Eating. Balanced Menus. 
Food for Bulk. Vegetarians. The Teeth. 



X. From Food to Blood, or the Process of Digestion 138 

Food Experiments with Cats. Under the X Ray. The 
Stomach during Digestion. Entrance and Exit of Food. Use 
of Bismuth. Undigested Substances. Emotions that Hinder 
Digestion. Happiness and Good Digestion. When to take 
Exercise. The Digestive Apparatus. Peristaltic Action and 
the Villi. Activity in the Food Tube. Relation of Chyle to 
the Villi. Food Waste. 

XI. Chemical Action and Digestive Fluids 154 

The Chemical Fluids of Digestion. Number and Structure 
of the Villi. Mistakes in Eating. Appetite and Gland Activ- 
ity. Flow of Saliva. Saliva and Carbohydrate. Milk Diges- 
tion. Proteid Digestion. Effect of Appetite on Digestion. 
Why we Cook our Food. Harmful Substances. 

XII. Large Glands: their Use and Abuse . . . . . 168 

The Liver — what it Is and what it Does. Effects of Alcohol 
on the Liver. The Kidneys — what they Are and what they 
Do. Effects of Alcohol on the Kidneys. Auto-intoxication. 
How to prevent Auto-intoxication. Headache and Auto- 
intoxication. Other Glands. Ill Effects of Snug Garments. 
Importance of Loose Clothing. The Two Body Cavities. 
The Rhythmic Movement of the Diaphragm. Aid to the 
Organs of Excretion. 

XIII. Why Nations rid themselves of Alcohol .... 186 

France and the Liquor Problem. The German Attitude. 
Russia and Prohibition. The English Method. The Japanese 
Liquor Law. The Movement in America. The Island of 
Newfoundland. Taxes, Crime, and Poverty. 

XIV. Body Temperature and the Skin; or Work, Heat, 

AND Fuel 194 

Testing the Effect of Heat on the Body. Sweat Glands as 
Protectors. Important Facts about the Skin. What the Skin 
Does. Taking Cold. Symptoms of a Cold. To Check a Cold. 
To Prevent a Cold. Internal Temperature. Warm-blooded 



animals. Why Clothes are Needed. Warmth through Exer- 
cise. Food as Fuel. To Reduce Fat. Educating the Body 
to Adjust Itself. 

XV. The Nervous System 211 

The Value of Sensations. The Hedge of Nerve Warnings. 
What Nerves are. Work of the Fibers. Different Sets of 
Fibers. Stimuli. Distribution of Nerves. Memory and the 
Cerebrum. Structure of the Brain. Cerebrum, Cerebellum, 
and their Convolutions. The Gray and the White Brain Stuff. 
Centers in'the Cerebrum. How the Skull protects the Cor- 
tex. Nerve Machinery. Spinal Nerves. What Accidents 
teach us about Nerves. Truthful and Untruthful Messages. 
Structure of the Neuron. Nerve Telegraph Stations. What 
the Gray and White Substances are. Fatigue and its Remedy. 

XVI. Training the Cerebellum and the Senses . . . 233 

The Work of the Cerebellum. Training the Neurons. Re- 
sults of Training the Neurons. Neurons and Facial Expres- 
sion. Four Great Truths about Neurons. Training the 
Senses. Machinery of the Senses. The Brain the Center 
of the Senses. Enlargement of Sense Centers. The 
Sense Centers of Laura Bridgman. Structure of the Eye. 
Treatment of Eyes; Headache, Eyestrain, etc. Structure 
of the Ear. Hygiene of the Ear. The Sense of Smell. 
The Sense of Taste. The Sense of Touch. 

XVII. Happiness, Health, and the Sympathetic Ganglia 252 

Vital Activities Independent of our Will. Vital Activities 
Controlled by the Ganglia. Structure of the Sympathetic 
Nervous System. A Nerve Plexus. Good Temper and Di- 
gestion. Why Happiness Helps the Body. Service from 
the Ganglia. 

XVIII. Alcohol and Efficiency 260 

Tests made with Students. Tests made with Typesetters. 
Experiments with Soldiers. Alcohol and the Neuron. 



XIX. The Menace of the Microbe 267 

The Public Drinking Cup. What a Microbe Is. How Mi- 
crobes Attack the Body. Protection for the Eyes. Why we 
Object to Flies. What Flies Eat. Safety through Carefulness. 

XX. Sanitation 277 

Country Conditions. City Surroundings. The Meaning of 
Sanitation. Cleanliness the Watchword. Sunshine and Air 
in Country and City. Rear Tenements and the Death Rate. 
New Tenement Regulations. Parks, Playgrounds, etc. The 
Sewage System. Pure-Food Laws and Food Inspection. 
Danger from Dyes. Canned Food. Patent Medicines. 

XXI. Our Foe — The Tubercle Bacillus 289 

Ravages of Tuberculosis. Dr. Koch's Discovery. Records 
from " Lung Block." East-Side Conditions. The Tubercle 
Bacillus: how Lodged and Distributed. The Nature of the 
Microbe. Bacilli in the Lungs. Danger from Sputum. 
Tuberculosis of the Bones. Consumption not Inherited. 
War against the Enemy. The Anti-Tuberculosis Crusade. 
Carelessness in Public Places. Public Sentiment. Rules of 
Prevention. Cure for Tuberculosis. Safety for Others. Five 
Tuberculosis " D's." Outdoor Air. Sleeping Outdoors in 
Winter. Open-Air Classes. 

XXII. The Choice: Pure Water and Clean Milk or 

Typhoid Microbes and Typhoid Fever . . . 308 

Former Conditions in Pittsburgh. Explanation of the Death 
Rate. How Typhoid Microbes reached Pittsburgh. Mi- 
crobes and Drinking-Water. Safety through Sand Filters. 
Lake Water for Drinking. Danger from Well Water. 
Sources of City Water. Rain Water. Typhoid Epidemic 
from Milk. Conditions of Clean Milk. Unclean Milk. 
Boiling Milk to kill Microbes. Pure Milk for Babies. 

XXIII. Cause and Prevention, or Safety from Microbe 

diseases 322 

Preventable Diseases. Measles and Scarlet Fever. Small- 
pox. Diphtheria. Hydrophobia. Yellow Fever and Malaria. 



The Hookworm Disease. Rules for those living in Hook- 
worm Regions. Whooping Cough and Mumps. Pneu- 
monia. Pink Eye and Trachoma. Disinfection and 

XXIV. Man's Friend and Defender — the Phagocyte . 338 

Cholera Microbes and the Phagocyte. How the Phagocyte 
captures Microbes. How Phagocytes Travel. Vigorous and 
Feeble Phagocytes. The Phagocyte as a Scavenger. What 
Pus Is. Cholera Epidemic and Alcohol. Hydrophobia and 
Alcohol. Alcohol and the Phagocyte. Phagocytes that 
Multiply for Emergencies. The Conqueror of the Phagocyte. 
The Man who Drinks. 



INDEX 361 




Taking the Body's Record. Certain cities are able to 
keep changeless records of their criminals who have 
been captured. City officials 
measure each man carefully 
— his height in standing 
and in sitting; the distance 
from the outstretched finger 
tip of one hand to the out- 
stretched finger tip of the 
other; the length and width 
of head, face, and right ear; 
the length of left foot, of 
left middle finger, and of 
left forearm. Scars are no- 
ticed and recorded; also 

the color of hair and eyes, ■^^""''^ "'^ ^^^""'^ '^'"^^ ^""^ 
-the shape of the nose, the number of teeth, etc. Each 
item is important as part of the final, full record. 


In addition, a photo- 
graph is taken. And, 
strange though it may 
seem, a photograph is less 
important than measure- 
ments in identifying a 
man if he is ever arrested 
again and brought to the 
police station. The reason 
is that our bone measure- 
A Caliper comiass measurhs the ments change little after 

Length of his Head ^g ^re twenty-tWO. Ever 

after that the size of face and head, the length of 
arms, of fingers, and of 
legs, remain practically un- 

This, then, is a sure 
and sensible way of keep- 
ing the record of a man. 
When a criminal is under 
examination, no matter how 
violently he declares that 
he has never been arrested 

before, the officers measure the middle finger is measured 
him at once, then search 

their written records. If they find any set of measure- 
ments which is a duplicate of those just taken, all the 


man's denials are in vain. Those officers know that never 
yet have two people been found who had precisely the 
same dimensions for all the bones which were measured. 

It takes but ten minutes 
for the officers to get their 
record of a man — photo- 
graph and all. But it took 
the man himself twenty-t\vo 
years to form the body which 
is now his physical record 
of himself; and the training 
began when he was very 

WheD Cartilage tarns to 
Bone. Notice any careful 
mother with a baby in her 
arms. See her firm hand 
against the back of the head 
as she holds the child up for 
a look at the world. She 
knows that for months there 
is more cartilage than bone 

in the supports of a baby's body, and that while bones 
are in this condition they cannot be trusted to do in- 
dependent work. 

Certain Indians have known this for centuries. A 
famous tribe that admired flat-headed men secured 

Chinook Baby 1: 


these heads for their boys by a clever contrivance. 
They simply fastened a board by a hinge to the head 
of the cradle and allowed it to press down upon the 
forehead of the baby whenever he was strapped in 
place. As months passed, the small skull not only con- 
tinued to grow but also set itself hard and firm in the 
desired shape. And, once firmly set, there was never 
any hope that the grown Indian could restore his head 
to the perfect shape which it had when he was borru 
Thus some of our bones and muscles are trained by 
other people before we are old enough to make decisions 
for ourselves. Yet, whoever is responsible for results, 
two laws of bone growth should never be forgotten: 

1. Many bones can be compelled to take a bend 
in this direction or that while the child is growing. 

2. Almost no bone can be forced to make a new 
bend after it is twenty years old. 

But there is other training which is more complex, 
and for which we ourselves are responsible. 

Making Our Own Records. On a certain day two boys 
entered the same shop and asked for work. The first 
boy was refused, the second was accepted. And the ex- 
planation lay with the bones and the muscles, which had 
made different records for the two bodies. The first boy 
walked with a shuffle and had a slouching body. Before 
he had spoken a word the business man who met him 
was unfavorably impressed and ready to reject him. 


The second boy walked as if he respected his body 
thoroughly. His head was erect, his shoulders well 
squared, and the vigor of his body gave the impression 
that he was in the habit of doing things with energy. This 
boy was accepted as promptly as the first was refused. 

How the Right Kind of Body Helps. Let two women 
enter a store or a schoolroom, a theater or a church. 
Which will be served most quickly, she who shuffles 
as she walks, has crooked shoulders and a head thrust 
forward, or the woman who steps forward gracefully, 
who walks as if her body were under her command, as 
if it were her true representative? Surely the second 
woman is queen wherever she goes. Without question, 
at every stage of growth the body proclaims the story 
of what has happened to it and of all that it has done 
with itself since it began to live. It is also true that 
we have it more or less within our own power, while 
we are growing, to make the records which are to 
represent us the rest of our lives. 

If a man by his own acts or his own carelessness 
must live miserably in a shanty when he might have 
lived gloriously in a palace, we are apt to blame him 
more than we pity him. 

Testing Yourself. For the sake of making discov- 
eries about yourself, stand before a mirror and study 
the outlines of your back, your chest, your shoulders, 
and your legs. Try to stand precisely as you do 


every day at home and at school, so that you may 
get a correct notion of the records your bones and 
muscles have made for you thus far in your life. 

The Same Hov at Another 

He lessens hU lung capacity 

Be keenly critical. Are you standing squarely on both 
feet? Are your knees bent or straight? Is your back 
erect enough to hold your head up where it belongs, or 
does your head droop forward so that your chin sticks 
out too far? Is one shoulder higher than the other? 
Is your chest rounded out like that of a soldier, or does 


it sag like a valley between your shoulders ? Rub your 
hand across your back to see whether or not a comer of 
a shoulder blade reaches out, like a young wing starting 
from the wrong place. 

If you can give creditable answers to these questions, 
your future course is easy. Simply keep on growing as 
you have begun, and in the 
course of time you will have 
the shape you wish. If, on 
the other hand, you are dis- 
satisfied with what you see, 
put each point right while 
still looking at yourself in 
the mirror. 

The Correct Standing Posi- 
tion. Stand with both feet on 
the floor, each bearing its 
own share of weight, both 
knees unbent, both shoulders 
square and on a level with 
each other. Draw in your chin until the back of your 
neck would touch a stand-up collar. Inhale a breath 
so full and deep that your chest looks like that of a 
drum major in his regimentals. Now your back has 
its correct shape for standing. 

The Correct Sitting Position. Make another test. Sit 
with feet squarely on the floor, back straight, head erect. 

Back View 

Notice hia shoulders and his 

curved backbone 


and chest raised. Are you comfortable? Can you draw 
a full, deep breath? Test this thoroughly. 

Now slip down in your seat, curve your neck forward, 
let your back be bent, let your chest fall in, and once more 

Right Position f 

try to take a full, deep breath. Notice that you cannot 
do this now, because you have cramped your lungs. 

Sit now with one elbow on the desk, or with one foot 
drawn up under you, or with some bend at the waist 
line that will give a twist to the spine near the hip. 
The objection to taking any one of these as the usual 
Dosition is that gradually the relation of the bones to 


each other will be so altered as to distort the body. 
In no wise does it harm any of us to twist this way 
and that, to bend as far as we can in one direction or 
another. Indeed, all such exercise is good for the body, 
provided no position is taken often enough, and held 
long enough, to become habitual. 

Lateral Curvature of the Spine. Dr. F. A. Schmidt, a 
scientific writer in Germany, says that Dr. W. Mayer 
examined the backs of three hundred and thirty-six girls 
and found that one hundred and eighty-nine of the 
number had what is called lateral curvature of the 
spine. He found that girls between seven and thirteen 
years of age had much more trouble than those who were 


under seven, and he concluded that the habits of sitting 
formed at the school desk explained the difference, be- 
cause the older children had spent more hours, days, and 
years in the schoolroom than those who were younger. 

Follow for yourself the work of muscle and bone, and 
understand what happens when a child gets into the 
habit of sitting at his desk with elbow up on one side, 
shoulder lifted, and body half screwed round. Notice 
that if you tip up one hip the spine curves sidewise, 
as a balance. If you raise one shoulder, it pulls the 
spine accordingly. Evidently each separate movement 
of the muscles of the back influences the curves of 
the spine, and the same curves repeated day after day 
at the same desk mold the bones, and the cartilage 


which lies between them, in wrong positions until they 
are as truly pressed into a new shape as if the change 
were planned for. 

The main objection to such curves is that if they 
are allowed to remain and to become habitual, they will 
interfere with the success- 
ful working of the large 
organs of the body. Then, 
too, when a curve becomes 
permanent — although it 
may be small — the nerves 
themselves are often af- 
fected by it, and the 
body suffers at the point 
whichis supplied by these 
nerves. A person endur- 
ing this pain may not 
know its cause, but his 
ignorance will not save 
him from suffering. 
How to prevent Lateral Curvature. Let us form habits 
that will help us to prevent spinal curvature. Children 
may save themselves by being careful to balance the ex- 
ercises which they allow the muscles of their backs to 
take. All that is needed is a little knowledge and a firm 
purpose. Whoever allows himself to be shaped by unde- 
sirable habits of muscle and bone will have cause for 

If this position is taken every day for 

long periods, the vertebrEC will become 



keen regret in later years. But he who, in his youth, 
controls his habits and shapes his body with care will 
never regret it. Instead, he will have a body that will 
be an honor to him for the rest of his life. Four rules 
will help: 

1. Do not sit day after day in the same twisted 
position. Change frequently. 

2. Do not carry a heavy weight of books on the 
same arm back and forth from school every day. 
Carry as few books as possible, and let each arm 
do its share of the work. 

3. Do not carry a baby brother or sister on the 
same hip every day. Indeed, it is best to do little 
carrying on either hip. The weight, placed just 
there, will tend to give a wrong twist both to your 
back and to his. 

4. If you must stand for hours at a stretch, 
learn to rest one leg by using the other. Don't 
let one side sag down habitually. Change sides. 


1. How do cities get and keep records of criminals ? 2. Which is the 
more accurate record of a person — a photograph or measurements ? 
3. After what age are bones set for life ? 4. Why does a mother sup- 
port the head of a young baby when holding it? 5. Give two laws of 
bone growth. 6. What effect does an erect, healthy body have on a 
boy's chance of success? 7. In what ways does the body tell facts 
about us? 


8, Test your own body to see if you stand correctly. 9. What 
sitting positions are objectionabie, and why? 10. What difference is 
there between sitting with a twist in the back once in a while and 
taking that position most of the time? 11. What must be guarded 
against ? 12. Do older or younger girls have more trouble from lateral 
curvature of the spine? 13, Why is this? 14. Mention various posi- 
tions that bring curves to the spine. 16. What objection is there to 
these curves ? 16. Give four rules for preventing them. 



The Strong, Bent Back. The coal heaver round the 
corner has a superb set of muscles over the working 
part of his back. They are so well developed that, as 
he stands bent over his work, 
it is evident that these mus- 
cles give him a back of tre- 
mendous strength. By their 
help he shovels coal for hours 
at a time, through the days 
and weeks of the year. More- 
over, when he has finished 
his day's work he does not 
seem overtired. He even jokes 
at the expense of his own 
back, for although it is so 
well developed and so tire- 
less, still the man himself ^^"''^ ^^ "" ^°'"' 
frankly acknowledges that it is sadly bent, and that by 
no effort on his part can he stand straight or walk as 
would please him best. He says that this is the price 
he has had to pay for the kind of work he has chosen. 


Multitudes of people have round shoulders developed 
in some such way as this. Notice their shape, know 
about their occupations, and draw your own conclusions. 
A bicycle rider whom I know 
has a back quite as bent, not so 
much from the work it has doju 
as from the position it has been 
allowed to maintain. It is mus- 
cular, strong, and efficient, but it 
never looks well except when he 
is working his legs fast on his 

Something must be wrong, and 
we wonder what it is. Here are 
these men, and multitudes of 
others, whose backs are well de- 
veloped, but who are so bent 
as to look almost deformed. For 
years no one could entirely ex- 
plain the cause of the combina- 
tion — a strong but bent back. 

Close observation and logical rea- 
Bent by Bicvcling ° 

soning have answered the ques- 
tion, however, for we learn that muscles stay in the 
position in which they do their heaviest work. 

Effect of Work on Stretched Muscle. A traveling man 
whom I know says that when, for a few weeks, he carries 


his suit case persistently with his right hand, the right 
shoulder becomes an inch or an inch and a half lower 
than the other, while at the same time it becomes stronger. 
This shows that a muscle can be lengthened even 
while it is being strengthened. 
Two oarsmen row with all 
their might. One does it with 
a straight back, the other with 
a curved back. Their work 
continues day after day, until 
one back is as strong and as 
muscular as the other. But see 
the results. One man walks as 
if he had spent his boyhood 
curved over a school desk with- 
out a thought about what was 
happening to his spine. The 
other man looks as if he might 
have spent those same years at 
West Point, with officers and 
fellow students who compelled 

him to stand straight whether he wished to or not. 
Yet the boyhood of the two men may have been 
alike. The difference just now depends upon their 
postures while they were rowing. Their muscles, when 
they walk, simply betray some facts about their recent 


To Balance Development. Fortunately, however, there 
is a happy outlook even for such people as are obliged 
to work with their backs bent, for there is another im- 
portant fact about this law of contracting and stretching. 
I give it concisely : 

Briefs vigorous exercise in the right position will undo 
much of the harm of long-continued exercise in the wrong 

If a man who works in a bent posture all day will 
spend five minutes a day in taking vigorous exercise 
with his back straight, alternately tightening hard and 
then relaxing the muscles of his back and neck, he 
will find that within one month there will be an im- 
provement. And the more faithfully the exercise is 
continued afterwards, the more good will it do. By 
this simple device a man may save himself from his 
rounded back and be able to hold his head where it 
should be. 

It often happens that the muscles of the chest be- 
come thin and flabby for lack of exercise, even while 
the back has become very strong. But these muscles 
may be saved. Throw the shoulders well back and exer- 
cise the chest muscles hard in this position. Exercise 
them while they are thus stretched, and they will grow 
large and prominent in spite of what your occupation 
may be. If the exercise can be taken oftener than once 
a day, it will be so much the better. 


The Law of Muscle Chaise. In this work of changing 
the shape and the power of a muscle, the greatest strain 
must be put on the last third or the last quarter of the 
contraction. Remember that each muscle is inclined to 
stay in the shape which it takes when it does its hardest 
work; in other words, the law is that doing a thing 
makes the part shape itself 
for that act. Evidently, then, 
to a large extent, we may 
develop our bodies accord- 
ing to our desire. Knowing 
this, a public lecturer — a 
doctor — told his audience 
that each man present could 
increase the size of his arms 
three quarters of an inch 
within one month and could 
increase his chest measure 

an inch and a half during 

■ I 1 lU f J.' Exercise for the Biceps 

the same length ot time. 

One Way of Developii^ the Muscles. To show what he 
meant, the lecturer asked his friend, a medical student, 
to illustrate the points one by one as he himself ex- 
plained them. The student was well knit and well built, 
no unnecessary fat concealed the shape of his muscles, 
and he was ready to show the other men what they also 
might do in behalf of their own development 


" Now," said the doctor, " show us the effect on the 
biceps of rotating the arm; the forearm; now rotate 
the leg — the big muscles; show that tensor. Now 
again will you go through four or five exercises that 
bring into play in succession first one arm, then the 
other, and so on ? " 

The student acted on the suggestions as fast as 
they were given. His smooth back and arms gave 
no sign of separate muscles 
while he stood quietly wait- 
ing to be told what to do, 
but as soon as he followed 
directions and used arm, 
leg, back, or shoulders, there 
sprang into prominence one 
set of well-developed muscles 

WELL.DEVELOPED MU.CLES ^f^^^. ^^^^^^^^ 

Antagonistic Muscles. The student held no apparatus, 
but used arms and legs as if he were pulling against 
some invisible weight. He was, in fact, pulling against 
the force of his other muscles — antagonistic muscles, 
they are called. Try this for yourself, with your forearm 
or with your back. Try to bring out one muscle and 
see how many others are called into action. The doctor 
then explained that muscles can be developed in this 
way with no apparatus whatever. " Muscles," said he, 
"can pull in one direction only; the opposite pull has 


to be done by antagonistic muscles." He made it plain 
that in arms, legs, and elsewhere, muscles are often 
placed in pairs, called flexors 
and extensors, which balance 
each other with their power 
of pulling. He showed that 
these opposing muscles can 
be developed without appara- 
tus by making flexor muscles 
bend the limb, and extensors 
straighten it out again. It is 
flexor and extensor muscles 
that help us close and open our hands; help us curl 
up our toes and stretch them out again vigorously. 

Exercise without Appara- 

tos. As he went on with his 
address, the doctor said that 
to make muscles develop, 
they should pull as hard 
as possible for a few seconds 
at a time, then let go com- 
pletely, then pull again for 
a few seconds, and so keep 
up the alternation for five 
minutes in the morning, for five minutes at night, and 
for ten minutes a day between times. " To develop 
arm or chest," said he, " put in the extra ten minutes 


whenever convenient" It appears, therefore, that in 
many cases the process of developing one muscle or 
set of muscles may be carried on without apparatus 
and without the gymnasium. 

Examine your own muscles. Decide which are firm, 
which flabby. If they should be improved, talk the 
matter over with any good gymnasium director. He 
will tell you what special 
daily exercise to take for 
special muscles. As for se- 
curing very big muscles, 
however, they are really of 
no advantage in the health 
line. Still the fact that up to 
a definite limit we have the 

Taking the Measurement power tO increase the size of 

arm and chest and leg proves once again how truly each 
of us is master and architect of the body we are building. 

Studying Muscle Structure. But what about the sub- 
stance out of which the body molds a muscle into 
shape and compels it to increase somewhat in size 
whenever it is forced to do unusual work ? Get a 
piece of lean corned beef from the butcher; have it 
boiled thoroughly; place a board over it and press 
down upon it hard enough to squeeze out all the 
liquid ; remove the board, and with a needle of some 
sort pick apart the fibers as well as you can. Pick 


them away from each other into finer and finer threads 
until you think you have reached the smallest ones 
of all. 

Now, \vith a good magnifying glass, examine one of 
these bits of beef muscle. You are able to pull them 
apart because the 
tough outside wrap- 
ping of each has 

been changed by ^ 


Bundles of Fibers. 
However large or 
small a muscle may 
be, and wherever 
that muscle does 
its work, whether 
in creatures that 
walk, fly, or swim, 
every bundle of 
muscle is made up „^^^^ ^^ different Shapes 

of fibers wrapped 

together. Shapes are different ; size varies — from those 
that draw an eyelid up and down, to those that kick a 
football to its goal; the work of each is different; their 
strength and power of endurance are different; but each 
bundle is a combination of individual fibers. A few of 
these are wrapped together as a small bundle, small 


Muscle Fibers 

bundles are gathered into bundles that are larger, large 
bundles become larger yet, and thus from smaller to 

larger are the muscles built up. 
Each is a bundle of other bundles ; 
each is adapted in size and shape 
to the special work which it must 
do; and every fiber in 
the bundles, large and 
small, is inclosed in 
what is called the sar- 
colemma. This sarco- 
lemma, then, is simply 
an outer wrap that 
separates each fiber from its neighbors. 

Connective Tissue. In addition, however, 
there is a close network of substance called 
connective tissue, which holds the individual 
fibers together. In this connective tissue 

are the tiny blood 
vessels and the slender nerves 
which supply blood and stimu- 
lus to each smallest fiber. Fine 
threads of connective tissue 
also stretch away from each 
end of the muscle fibers and 
help to form the tendon. Each 
tendon is fastened to a bone. 

End of a 
Muscle Fiber 

It shows fine 

threads which 

help form the 


A Bundle of Muscle Fibers 

Each is covered with its own 

sarcolemma ; connective tissue is 

between the fibers 


Tendons. Any tough bundle of tough fibers which 
holds muscles to the covering of the bone is called a 
tendon. Examine your wrist. Open and shut your 
hand by the use o£ extensor and flexor muscles. Notice 
the movement of the long slender tendons that connect 
the fingers with muscles in the arm. The foot is moved 
by tendons that reach up to the mus- 
cles of the leg. This use of long ten- 
dons gives the body its slender wrists 
and ankles. Some muscles end in ten- 
dons fastened to bones at a distance. 
Some have short tendons fastened to 
bones near by. But, whether long or 
short, whether large or small, all ten- 
dons are needed to help muscles pull 
the bones in definite directions. And tendon, gkeatlv 
the muscle itself does its work by con- magnified 

iracting and relaxing. "tZXr 

Draw up the muscle in the calf of the 
leg. It has tendons fastened to the lower end of the 
thigh bone and to the heel bone. The contracting of the 
muscle is done between these two firmly held points, 
and because of this contraction we are able to walk, 
run, dance, and kick. The biceps muscle of the arm has 
tendons which hold one end of it to the shoulder, the 
other end to a bone in the forearm. When the mus- 
cle contracts, the lower end is drawn up, not because 


the tendons contract but because they cHng to the 
bones and so do the pulling. The wonder is that these 
tendons do not more often suffer under the sudden 
strain which we sometimes put upon them. When they 
do give way — as happens in a sprained ankle — it is 
often a more serious matter than a broken bone, because 
the outside covering of the 
bone is sometimes pulled 
away with the tendon, and 
the ends of a broken bone 
knit together much more 
easily than do the torn ter- 
minations of a tendon. 

Remember that when any 
muscle pulls any bone it is 
because each muscle fiber 
in the bundle has shortened 
itself and grown thicker. 
Indeed, it is the shortening 
of the fibers that compels 
the pulling. Double up 
your arm hard and prove this. The muscle is thicker 
because of the united work of thousands upon thou- 
sands of fibers. Although each separate fiber, then, is 
a part of the muscle as a whole, each is also a small in- 
dependent center of power, doing its own work. But no 
single fiber carries its independence very far. Generally 

1 Jfuda 
f fiber 







(After Schmidt) 


when its neighbors receive a command to go to work, it 
receives the same command. When they rest, it rests too. 
When they are destroyed by age or death, it endures all 
that they endure. Yet, after all, the work of the millions 
of fibers that are held to- 
gether by connective tissue 
in a single muscle is really 
the sum of the work which 
the fibers do separately. 

What makes Tough Mus- 
cles. More than this, it is 
the amount of connective 
tissue between the fibers 
that explains the difference 
between tough and tender 
meats. With age and ex- 
ercise this tissue gradually 
thickens its substance dur- 
ing life, until finally certain 
muscles become too tough 
to be eaten without long 
boiling or steaming. 

When, therefore, we speak of tough and tender meat, 
we really refer to muscles in which the connective tis- 
sue has or has not been toughened by age or exercise. 

Let an athlete bend up his arm. You may try to 
press it with your hand, and it will resist you almost 

Muscles Tightened and Shortened 

(After Schmidt) 


like a piece of wood. This is no mystery, for you 
understand that each fiber in that muscle has been 
toughened by use. If such a muscle were found in the 
shop of a butcher and offered for sale, a wise cook 
would refuse to buy it, because even boiling would not 
make it tender. But tough muscle in the arm of an 
athlete means that it is in prime working condition. 

A Running Broad Jump from One Foot 

It shows the work done by different muscles from the moment the man jumped 

until he stood on his feet again 

(After Schmidt) 

Two Classes of Muscles. The muscles which we have 
been studying belong to the skeleton. They are always 
attached to bones and are therefore called skeletal 
muscles. There are two great classes of muscles: 

I. Voluntary muscles^ of which there are five 
hundred, are under the power of our will. Through 
them we walk, run, climb, and swim ; through them 
we talk, sing, play the piano, and crown ourselves 
with glory on the athletic field. Most of them are 
fastened to bones that are movable. Hand and 
head, arms, legs, fingers, mouth, tongue, eyelid, and 
eyeball — all are under our control because they are 

SuPEBFiaAL Muscles of the Body 
Each is fastened to bones that lie underneath 


moved by our voluntary muscles, which contract 
and relax at our bidding. Not so, however, do 
muscles of the other sort. 

2. Involuntary muscles are independent of the 
bones, independent of our will, and far too numer- 
ous to count. They form the muscular sac of the 
stomach and the muscular tube of the intestines. 
They give muscular power to the arteries and form 
the entire substance of the heart. It is, in fact, the 
ceaseless contracting and relaxing of the involuntary 
muscles of our heart that keeps us alive, through 
the circulation of the blood. When heart muscles 
stop, life must soon stop. Each air sac of the lungs 
has its muscular wall, and each individual organ of 
the body has its own supply of involuntary mus- 
cles in constant service. All these are deaf to our 
commands, but they continue to be busy whether 
we sleep or wake, whether we stand or sit, walk 
or run, whether we laugh or cry. Whatever we do, 
they are unceasingly occupied with the internal 
work of the body, pumping the blood through heart 
and blood vessels, caring for the food we eat, and 
carrying on those vital processes over which we 
have no conscious control. 
Weight of Muscles. Taken as a whole, the muscular 
machinery of any human being is as heavy as all the 
rest of his body weighed in a lump. A few separate 


muscles are given in the picture on page 27. Each does 
its own separate work, and all help in what the body 
does for us. But perhaps the biceps is the muscle best 
known to every boy. 

Study the muscles on the chart and locate as many 
of them as possible on your own body. The intercostal 
muscles do not appear, being hidden under other mus- 
cles. They hold the separate ribs to each other. 


1. Why do coal heavers have strong, bent backs? 2. What law 
explains such a back? 3. Mention such occupations as you think may 
change the shape of the body. 4. Give the second great law about 
muscles stretching and contracting. 5. How may a man who works in 
a bent position save himself from being permanently bent? 6. How 
can you show what muscles can do? 7. If a person exercises without 
apparatus, what does he pull against ? 8. What is an antagonistic mus- 
cle? 9. How can muscles be developed without apparatus? 10. How 
often, and for how long a time, should such exercises be taken ? 

11. Define muscle fiber. 12. How may we examine the structure of 
a muscle closely ? 13. Tell about the size and shape of different muscles. 
14. Tell how muscles are formed. 15. What is the sarcolemma ? 16. What 
is connective tissue ? 17. What lies within it ? 18. Of what use are the 
fine threads of connective tissue that stretch away from muscle fibers ? 
19. What do they help form? 20. What is a tendon? 21. To what 
bones are the muscles in the calf of the leg fastened ? 22. What does 
the biceps pull up ? How ? 23. Why is a torn tendon often worse than 
a broken bone? 24. When is meat tough ? tender? 25. Describe volun- 
tary muscles. 26. What is the work of involuntary muscles ? 27. Com- 
pare the weight of the muscles with that of the rest of the body. 
28. Study the chart and name five muscles. 



Bones and Muscles. A certain teacher who owned a 
skeleton used to throw it over his shoulder when he 
carried it from the storeroom to the lecture room. And 
as he walked it hung from his back, a clattering set of 
dangling bones. It is true that the separate bones were 
held together at the joints by artificial contrivances, but 
that was all. The skeleton could not have stood on its 
own unaided legs. Those who saw this group of bones 
and were instructed, understood as never before that 
bones are as dependent on ligaments and muscle to 
keep them together as are tendon and muscle depend- 
ent on bone to hold them in place. 

Bone Structure. Examine a bone fresh from the 
butcher's. Notice the outside — firm and closely woven,, 
as it has to be to supply a surface for muscles to hold 
to. This bone-covering is the periosteum. It is a tough 
membrane, and tendons from the muscles are fastened 
to it. 

Within the bone we find the texture much looser thaa 
that of the periosteum. We know now how it happens 

that the bone is not only large and strong but light and 


The Human Skeleton 
A, skull {22 bones) ; B, spinal column (33 vertebra) ; C, sternum ; D, ribs {12 on 
each side); £ clavicle (i on each side) ; F, scapula (1 on each side); C, humerus; 
H, radius ; /, ulna ; /, carpal bones (7 in each wrist) ; fC, metacarpal bones (5 in 
«ach hand); Z, phalanges (14 in each hand); M, pelvis (4 bones); N, femur; 
O, patella (i in each knee) ; P, tibia ; Q, fibula ; J{. tarsal bones (7 in each ankle) ; 
S, metatarsal hones (5 in each instep) ; T, phalanges (14 in each foot) 


firm. It is indeed by no means a solid substance. A 
magnifying glass shows numerous tiny spaces in the 
body of the bone. One may also see smooth channels 
on the outside, along which the blood vessels ran, and 
tiny openings from the surface to the interior, into which 
the smallest blood vessels went to keep up the life of 
the bone. 

Chemical Composition 

of Bones. A chemist 

will take a bone and 

keep it in acid for a 

while. He will then tell 

us that he has taken 

out all the lime salts 

■■• f and has left nothing 

'° but organic, or animal, 

igh the matter. He may now 

lo each tie the bone into a knot 

to show how flexible it 

is. Taking another bone he will hold it in fire for a 

while ; then, when touched, the whole structure falls to 

pieces — a heap of white powder. " This is mostly lime," 

he says. " I have burned out the organic part." A cook 

will take a meatless bone, boil it for several hours, and 

secure a jelly to add to her soups. This is gelatin from 

the animal matter of the bone. It proves that even a 

bone is of value and should not be wasted. 

Blood vessels and nerves 

canals, and chese canals ai 

other by channels yet 


Young and Old Bones. These and other experiments 
show that bones are made up of so-called lime and an ani- 
mal substance which becomes gelatin on being cooked. 

We also learn that the bones of old people 

contain much lime and 

are very brittle, while the 

bones of a child contain 

far less lime and are less 

brittle. This fact makes 

it unsafe for aged people 
Tied in a to have even a tumble on 

the sidewalk. Younger 

After acid has ° 

taken the lime bones Can save themselves 

*'°'"" by bending a trifle. 

We understand now why children 
have so much power to shape their 
bones while they are young. It is be- 
cause these bones are not yet firmly 
set with lime. 

Decide for yourself why each of 
your bones has its own particular 
shape. Study the picture of the 

, : , , - , A Bone cut 

skeleton and learn as many or the through lengthwise 

names as your teacher requires. The outer layer is com- 

Shape and Size of Bones. Each bone 

pact and fim 
substance is a network 

has its own particular shape; long of canals and spaces; 

'^ ^ " thus are bones both light 

ones for legs and arms ; flat ones tor and strong 


shoulder blades, breastbone, and 
hips; curved long ones for the 
ribs ; curved fiat ones for the skull. 
These latter are so closely inter- 
locked that the head seems like a 
solid, single bone. There are queer, 
jagged bones, one above the other 
in a column, for the back, and many 
small bones of hand and foot deftly 
held together by ligaments. Each 
bone does its part in supporting the 
muscles and other soft parts, and 
in making them serviceable to us. 

The shafts of the long bones are 
hollow, with delicate fat, called mar- 
row, in the center. The short, flat, 
and square bones are spongy inside, 
with red marrow in the spaces. 

The human skeleton is made up 
of two hundred separate bones, each 
with its special name. But perhaps 
the most important group is the 
column of vertebrae which forms 
the spine. 

The Spinal Column. Many a man 
Lower i-eg with its jj^g Uygj for years without an arm. 

Muscles and Tendons , . , 

(Alter Schmidt) without a leg, without bones of 



various sizes and shapes; but no man would ever be 

able to live for a moment without that column of small 

bones that holds his head erect, 

that keeps his ribs in place, and 

that guards the treasure of his CirvUai 

spinal cord. 

In the spinal column each sepa- 
rate vertebra is held to the one 
above it and to the one below it 
by muscles and ligaments on each ^ 

side, and because of their muscles [orDonai) 

and ligaments these individual ver- 
tebra are no more responsible for 
the shape they take, or for the 
twists and curves they join in mak- 
ins: when a gymnast bends his back 

r ■ , ■ 1 . . Lumiar 

from side to side, than are the 

dumb-bells and the pulleys which 

the same gymnast uses; for the 

bones of the spine simply rock 

back and forth or sideways upon 

. . ,. -^ , A Side View of the 

each other, according as muscles smnal Column 

on this side or that give the 
needed pull and move the bones. 

To prevent too much jarring, each vertebra is sepa- 
rated from its neighbor by a thin elastic cartilage which 
acts like a cushion between them. 

Each group of vertebrae has 


Wedge-Shaped Vertebra. Just here recall a few facts. 
Young bones are somewhat yielding; they take new 
shapes if they are put under special, oft-repeated pres- 
sure. A child at a school desk 
easily gets into the habit of sit- 
ting with the vertebKe pressed 
against each other at the same 
angle every day. Muscles do the 
pulling ; they grow strong as they 
are exercised. In the meantime. 
Vertebra sees from also, the separate vertebrae are 
yielding to pressure. On one side 
they are growing thinner; on the other side, not being 
pressed upon, they grow thicker. The result is that some 
of the bones of the back will become wedge-shaped ; 
and, sad to say, a back that has 
developed wedge-shaped vertebra; 
— vertebrje that have kept their 
wedge shape until they are hard- 
ened for life — can never hope to 
be straight again. 

Bones Enlarged by Work. Cer- 
tain other bones may, however, be 
changed by what they are com- 
pelled to do. To make them rougher and larger you must 
work the muscles which are fastened to these bones ; work 
them hard ; be persistent, and the result will come. 


Pressure was too often on the same aide 


In studying human skeletons it is not difficult to 
point out the bones of such persons as did vigorous 
muscular work, by their heavier and rougher character, 
while the thin walls and fragile internal substance of 
other bones show that the muscles that moved them 
were paralyzed or wholly useless during life. 

Blocks showing how the VERTEBRit are held together 

BY Ligaments and Muscles 

/, ligament ; m^ muscle 

Evidently, then, active exercise leaves its mark even 
on the bony part of the body. Thus, without making 
any close examination of our own separate bones, we 
may know, by the exercise we give them, what their 
prospects are year by year. 

The Foot under Pressure. Nor are vertebrae the only 
bones to suffer under pressure. Think of the bondage 
of the feet, both in China and in other lands. 


As I looked at the small, deformed feet of our friend, 

the Chinese lady, I knew what had happened to the 

■ bones that made up the bulk of the huge ankle above 

the. shoe. No one saw this ankle. All we saw was 

Chinese Shoes Two and a Half Inches Long 
The huge ankle shows how deformed the foot really is 

the dainty, handmade shoe, two and a half inches long, 
embroidered in silk of lovely shades, and made of cloth 
and silk with a leather sole. But we knew that within 
those shoes the toes were drawn in under the foot, the 
heel drawn forward to meet them. We knew that from 
early childhood those feet had been held in bondage 


by bandages, that muscles and tendons had been kept 
from growing, and that bones had taken strange new 
shapes of deformity. Fortunately for children in China, 

the government now forbids foot-binding. And what 
about uncomfortable shoes for ourselves? 

The Bones of the Foot. When you see your own bare 
foot to-night, compare its natural shape with the shape 

of fashionable shoes. Then consider the following facts 
and decide what the sensible course of action is: 

1. Each foot is made up of twenty-six small bones. 

2. These bones are joined to each other by 
ligaments and muscles. 


3. If the arch of the foot is flattened, health is 
apt to suffer. Indeed, it is so serious a matter to 
be flat-footed that men with this handicap are 
refused admittance to the 
United States army. Test the 
condition of the arch of your 
own foot by dipping the bare 
sole lightly in water, then press- 
ing it on blotting paper. The 
imprint made will show the fiat 
or the arched instep. Those 
who stand still for hours every -^ '^ 

day should save the arch by 

■' , , ^ A,a.n arched foot ; B, a 

resting the weight of the body flat foot 

first on one foot, then on the (Aft« Schmidt) 

other. If you have any tendency to flat feet, help 
yourself by standing with toes turned inwards and, 
while in this position, rising as high as you can on 

ii Foot deformed by Faskionabi.e Shoes 

(After Sohmidl) 

your toes. Do this one hundred times twice a day, 
or rise and fall on the toes until the muscles are 
tired. The results will be satisfactory. 


4, No foot can exercise itself easily unless each 
muscle, bone, and ligament is allowed to move with 
Rules for Foot Hygiene. The following are rules for 
foot hygiene: 

1. Wear shoes with soles as broad as your foot 
is when you stand with no shoe on. 

2. Do not lace shoes so snugly about the ankle 
that the pressure will interfere with the circulation 
of blood. Cold feet often come from tight shoes, 
tightly laced. 

3. Let the heels of your shoes be broad and low. 

4. Never wear tight garters. They interfere with 
the movement of the blood through the blood 
vessels. Wear side garters. They do not bind the 
blood vfssels. 

5. Remember that tan shoes are rather better 
than black shoes for summer wear, because they 
do not keep the feet so warm. 

6. Keep the feet dry and warm, but if possible 
avoid overheating them. 

7. Be sure that your shoes are large enough to 
give your toes as well as your ankle a chance to 
move and to be useful when you walk. 

Joints and their Ligaments. And what can be said 
about joints, the movable meeting place of the bones? 
By every twist that you can make, try to decide where 



your joints are and how each works. You will find 

that some work back and forth like a hinge, while 

others have the power to move back and forth and 

sidewise too. The different kinds of movement are 

The Shape of the Foot and the Shape of the Shoe 

Dotted lines show the natural shape of the foot ; solid lines show the sole of the 
shoe. A, correct shape ; By the large toe is drawn in too far ; C, the shoe is too 
narrow. If you wish a comfortable and a well-shaped shoe, get one that is 
wide enough, but longer than you need. This will give you the effect of having 

a slender foot 

the result of different kinds of joints. Each is needed 
in its particular place. 

The Hinge Joint. Begin with the hinge joint where 
your skull is joined to the upper end bone of the spine. 
This allows you to bend your head up and down, and 



nothing more. But just below, between the next two 
bones, is a joint of another sort. This allows you to turn 

your head from side to side. Thanks 

to the two joints acting as one, you 

can move your head in any direction. 

Elbow and knee, fingers and toes — 

all act on the plan of the hinge. Test 

them for yourself. 
A Ball-and-Socket 

Joint. Whirl your 

arm round and 

round and know 

that you are using 

the most movable 

joint in the entire 
body. It is a so-called ball-and-socket 
joint. The hip is supplied with another 
of much the same kind. Here the socket 
(in the pelvic, or hip, bone) is shaped 
like a cup, and within it is the round 
head of the femur, or thigh bone. 

When we think of the work which 
the hip and the knee have to do for us, 
and of the strain we are ready to put 
on them at any moment, we under- 
stand why the hip and knee joints should be among 
the firmest and the strongest parts of the whole body. 

Cut throtgh the 

Hinge Joint of the 


Bones and Joints 
of the Leg 


Ligaments help make the joints. These bands of tissue 
are firm and white and tough, Hke tendons. Like ten- 
dons, too, they are slow to heal when torn. But they have 
nothing to do with muscles. Instead, they fasten bones 
to each other, while tendons fasten muscles to bones. 

The knee is a won- 
derful structure of 
bones and ligaments. 
It is a great hinge 
joint supplied with 
ligaments which allow 
it to bend one way, 
but which absolutely 
forbid any bending in 
the opposite direction. 
If it were not for liga- 
ments which hold the jjjp jo,nt drawn open 

bones together in a Notice the ligament which holds the ball in 

definite relation, our its socket 

knees would bend backwards and forwards with equal 

ease, and walking would be forever out of the question. 

Two kinds of joints are thus seen to be most promi- 
nent in the body of man: (i) hinge; (2) ball-and-socket. 

The Synovial Fluid. The ends of bones which form 
joints are covered with smooth and shiny cartilage, or 
gristle, to which ligaments are fastened. Also, within 
the joint itself, there is a small, delicate bag, holding a 


few drops of slipjKry liquid — synovial fluid. This fluid 
lubricates the joints and helps their smooth movement 
We have now learned that the ends of our bones are 
shaped to meet each other; that they are carefully fitted 
together ; that tough liga- 
ments hold the one to 
the other; and that mus- 
cles end in tendons which 
draw the bones in such 
directions as the joints 
allow. But bones move 
only when the heart beats. 
We study this subject next 

1. How do bones help mus- 
cles ? 2. How do muscles and 
tendons help bones ? 3. Describe 
the outside and the inside of a 
fresh bone. 4, What does a 
magnifying glass show about it > 
5, What can a chemist do to 

; Kner Joi 

Notice the ligamenta that hold the 

bones together bone ? 6. What can a cook do 

with a bone? 7. What two im- 
portant substances form bone ? 8. Why do aged people need to be more 
careful than children ? 9. Describe the different shapes bones may have 
and give the number of bones in the human body. 10. What is a vertebra ? 
11. How many vertebrse are there? 12. How are they held together? 
13. What lies between the vertebras to prevent jarring ? 14. Explain how 
vertebrae may become wedge shaped, and tell what harm results. 


15. How many bones are there in the foot? 16. How are they 
joined together? 17. Which is more desirable, the flat or the arched 
instep ? 18. How can you decide which kind you have ? 19. If you 
have a tendency to flat feet, how can you help save the arch ? 20. Why 
should the feet be uncramped ? 21. In buying shoes, what points should 
be kept in mind ? 

22. What fastens muscle to bone? 23. Describe how muscles help 
move a bone. 24. To what bones are those tendons fastened which be- 
long to the muscle which forms the calf of the leg ? 25. Is the contract- 
ing done in muscle or tendon ? 26. Describe the joints which lie between 
the skull and the spine. 27. Where do we find important ball-and-socket 
joints ? 28. What sort of joint is there at the knee ? 29. What is the 
difference between a tendon and a ligament ? 30. Name two kinds 
of joints. 31. Where do you find examples of each? 



The Pulse. Let some one hold a watch while you and 
perhaps your friends test yourselves in various ways. 

Stand with your finger on your pulse at the wrist, 
and when the person who holds the watch says, " Get 
ready — begin," let each one 
start to count the regular 
throb of the pulse which 
he feels under his finger. 
Let him keep on counting 
until, at the end of one 
minute, the timekeeper says, 
" Stop." You will then have 
your count 

If you are not excited, if 
you have not been exercis- 
ing hard beforehand, if you 

Counting THE Pulse Beat ^^^^ ^^^[g ^^^ mistake in 

your counting, the number of beats which you feel will 
show what your regular, everj'day pulse beat is. You 
have secured your standard for the standing position. 
You are ready for the next test. 


Stand perfectly still and, while the timekeeper fol- 
lows the time again, open and shut your hand as fast 
and as hard as you can for an entire minute. Then 
once more count your pulse. You may find that it has 
gained a trifle in the number of beats. This will depend 
on the vigor with which you 
have worked the muscles of 
your hand. But the muscles 
there are small, and you 
will not get much result in 
the way of a more rapid beat. 

Turn, therefore, to the leg 
muscles. Use them vigor- 
ously. Run up one flight of 
stairs and back, and at once 
count the pulse again. You 
will find a marked change. 
From eighty or over at the 
start, you have probably in- 
creased the count to one he counts bo™ Pulse Beat 
hundred and twenty or more. *"° heart beat 

The Pulse Beat and the Heart Beat. In addition to the 
above tests make one more. While the fingers of your 
left hand are feeling the pulse in your right wrist, place 
your right hand over your heart. You will discover that 
the pulse beat and the heart beat occur at the same in- 
stant And now, if you were not uncomfortably out of 


breath after the run up one flight, try two flights and 
notice that the number of beats has increased both at 
the wrist and at the heart. You have proved for your- 
self that the pulse beat may be depended on to show 
the rate of the heart beat. 

The Effect of Exercise on the Heart. The following 
table shows what such exercise did for a small class 
of children in a New York school. The letters of the 
alphabet stand for the names of the children. 


Normal After Short, 

Pulse Quick Run 

A 85 130 

B 83 142 

C 71 113 

D 85 95 

E 85 113 

F 88 120 

G 83 95 

Each child was tested again within a minute after 
the run, and already the pulse was found to be beat- 
ing more slowly. This rapid return to the normal beat 
is the sign of a healthy heart. 

Test yourself in other ways. Count your pulse when 
you get up rested in the morning and when you go 
to bed tired at night. Count it before and after your 
cold bath in the morning. Count it before and after 


any kind of exercise that interests you. For example, 
run to school one morning, walk another morning, and 
compare the results of both with your standard. Com- 
pare the number of beats of the heart that has done 
hard work with those of 
the heart that has done 
light work, and see what 
gives your heart the 
most exercise. Through 
all this you learn what 
the power of your own 
heart is. 

Already you know that 
exercise makes the heart 
beat faster, and that the 
larger the muscles are 
and the harder the work 
they do — running, for 
example — the more ex- 
ercise will the heart have. 
You have also learned 

that the pulse may al- We are well or m, we live or die. by the 
1 1, work it does or fails to do 

ways be trusted to tell 

important facts about the action of the heart. 

What the Pulse Beat Proves. It is for this last reason 
that a doctor feels the pulse of his patient. By the, 
regular or the irregular beat of that pulse, by the way 


it hurries or by the way it drags, he is guided in his 
judgment as to what the condition of the patient is 
and what ought to be done to help him. The heart, 
indeed, is one of the vital centers of our activities. 
We are well or ill, we live or die, through the work 
which it does or fails to do. Yet ignorant persons often 
give it either too much or too little exercise. Many frail 
women fear to take exercise lest they overtax the heart, 
while bicycle .riders, and others who exert themselves 
beyond reason, often overtax the heart until it is injured 
for life. This is also true of boys who run long or hard 
races before their hearts have been trained for such 
violent exercise. 

The Heart Muscle. It seems that the heart is a strong 
hollow muscle about as large as the fist of the one 
for whom it works, and that even when it is not 
overtaxed it does more work than any other muscle 
in the body. It lies under the ribs, between the two 
halves of the lungs, and keeps up its beating from birth 
to death. Even though it is so constantly active, still, 
like every other muscle, exercise gives it strength, while 
lack of exercise leaves it weak. 

In training this important muscle let us remember 
that most human beings have sound hearts that need 
to be treated in a reasonable way. 

Overtaxing the Heart. A neighbor of ours had taken 
no special exercise all winter, but when spring came 


he began abruptly by playing one set of tennis after 
another without resting. The result was that for many 
days and nights his heart kept up a rapid beating. For 
three weeks, indeed, it refused to come down to nomial, 
and during this time the man dared take no exercise 
whatever. He knew it 
would be unsafe. 

If he had been careful 
to begin his tennis-playing 
gradually, increasing the 
amount from day to day, 
he would have done better 
work, would have spared 
his heart the overstrain, and 
would have saved himself 
weeks of weariness. 

TrainiDg Heart and Mus- 
cles T<^ether. Watch those 

who race to catch a car. at the c« moment 

By the way they breathe you may know what the heart 
is doing. You will also be able to tell which of the 
running men and women have trained their hearts for 
sudden sprints of violent work, and which are pressing 
untraiiied hearts into unusual service. College students 
often run by the mile across the town and out into the 
country. They are training not only the many muscles 
of their legs but also the one muscle of the heart and 


their breathing apparatus as well. They wish to train 
their leg muscles, while at the same time they secure 
for themselves hearts and lungs that will help each 
other and be useful as long as their legs are able to 
keep up the running. 

A doctor whom I know speaks of a man whom he 
himself trained. He says: 

When I took charge of him the man could not run as far as from 
here to the door without fainting. He simply had a muscularly weak 
heart, excited by nervous shock and overwork, worry, deficient nutri- 
tion, and lack of sleep. I first discovered that there was no organic 
disease. Nothing but plain building up of muscle was needed. Then 
I went to work and started to build up that muscle. I would have him 
run a few steps and then lie down three minutes, then run a few steps 
more and lie down. I stood by, keeping track of his heart, not allowing 
him to do enough work to send it above one hundred and not letting 
him run again until it got back to normal. I kept him at it half an 
hour three times a day, from day to day increasing the doses ; that is, 
I stuck to the medicine, but I gave very small doses, — doses suited 
to the strength of heart he then had. In three months that man could 
run eight miles an hour with great ease and comfort. Since then he 
has not known that he has a heart. 

Overstretching the Heart. This doctor also speaks of 
a friend of his who ran up eight flights of stairs be- 
cause of a fire, and so overstrained his heart that it 
has never been right since. 

This shows that when the heart has done what it 
comfortably can, and then has to do still more work 
and keep it up, it stretches too much for its own good. 


And worse still, if stretched badly enough, it stays 
stretched. This is part of the trouble with the over- 
worked heart of the bicycle rider. Athletic trainers 
understand these facts thoroughly. It is therefore as 
much for the sake of the muscle of the heart as for 
the benefit of leg muscles that they insist that only 
those who have been trained for the contests shall be 
allowed to compete in athletic games. Otherwise the 
untrained person might faint in the midst of the sport, 
harming himself and frightening everybody. 

The safe rule is to give the heart all the exercise 
it can comfortably take at one time, and to increase 
the amount as fast as its power increases. 

As a rule, the actual size of the normal heart is large 
or small according to the work it has had to do. Animals 
kept in cages and captivity have been examined after 
death, and their hearts have been seen to be smaller 
than the average heart of wild animals of the same kind. 
In proportion to his size, the heart of a stag is about 
twice as large as that of a pig. The reason is plain. 
The stag lives by exercise which makes the heart 
work; the pig, except in the wild state or in pasture, 
seldom takes any unusual exercise. 

Heart Development. Provided one does not undertake 
too much, nothing is better for heart development than 
exercise which calls for endurance. A quick run for a 
minute, or a brisk jog trot lasting five minutes, is as 


good as anything that can be devised. Run a little as 
you go to school in the morning, then walk a little. 
Run only as much as you can quickly recover from. By 
your pulse beat and by the way you keep your breath 
or lose it, you will know what you may do. Begin with 
little exercise, for you are going to make steady gain 
whatever your starting point is, and you gain most by 
going moderately at first. 

Throughout his entire life the person who has a 
well-developed heart will also have more vigor, more 
power to endure, more courage than he otherwise would 
have. The result is worth working for. 

Harvey's Discovery. This we all know now, but three 
hundred years ago even learned . men were ignorant 
both about the heart and about its activities. Then 
came Harvey's great discovery. In 1616 we find 
William Harvey, an English physician, lecturing in 
London. He was only thirty-eight years old, and already 
his medical reputation was very great. When he died, 
at the age of seventy-nine, he had changed certain 
beliefs of the human race. Nor did this come about by 
accident. During his active life, whenever he had the 
opportunity for it, — whether with men or with animals, 
whether with those who were well or ill, alive or dead, — 
he studied the body and gave special attention to the 
action of the heart and to any connection which it 
might have with the blood supply. 


Arterial and Venous Blood. In the case of wounded 
animals, at different times he laid his hand on the heart 
and noticed that with each throb the blood left the 
wound with a spurt, and he saw that blood which 
spurted in jets from a wound was always of the bright- 
red kind. This is now known as arterial blood. 

Then too he observed wounds that bled in a dif- 
ferent way. The blood simply poured out in a quiet, 
dark-purplish stream, and there was no sudden increase 
of flow with the heart beat. This is venous blood. He 
found that the sam.e was true for wounds in man and 
beast alike — that bright blood came in jets, while dark 
blood came in a quiet stream. He saw too that when- 
ever the heart beat slowly the pulse at the wrist was 
slow too. 

These important observations, added to many experi- 
ments which he himself made, drew Harvey's thoughts 
more and more to questions about circulation. It then 
occurred to him that the heart might be a special 
machine for pumping bright-colored blood out into the 
arteries, and the thought of such a possibility was excit- 
ing even to himself, for no one had suspected this before. 

Arteries and Veins. Through yet other experiments 
and constant thought on the subject, his surmises grad- 
ually changed to convictions. He became very sure that 
every pulse beat in the artery at the wrist meant that 
the heart had pumped a fresh supply of blood into the 


large artery — the aorta — which is joined directly to it, 
and that the elastic tubes had expanded throughout their 
entire length to make room for the blood. He knew, as 
we do, that the largest arteries are buried deeper in the 
body than the veins, and that only at certain spots do 
they come near enough to the surface to allow us to feel 
the effect of the heart beat. He noticed that there is 
never any throb in a vein, and this strengthened his 
conviction that no vein ever receives blood directly 
from the throbbing heart. 

The Work of the Heart. By traveling the road which 
he took, we have come upon Harvey's first great 
discovery : tlie heart pumps blood into the arteries. 

The scientific world was greatly excited over this 
announcement. But Harvey himself went quietly on 
with his investigations. He used his own methods of 
measurement, which are different from ours. But the 
amount of blood in the human body was the same 
then as now, and it was this blood supply that Harvey 
studied and that we also are studying. He saw that the 
heart pumps by contracting and expanding; that the 
average human body holds about six quarts of blood; 
that the heart sends about half a tumblerful of blood 
into the aorta every time it contracts; and that, since 
the heart beats about seventy times a minute, an enor- 
mous quantity of blood must be squeezed out of it 
during each half hour. 



He did some multiplying, and decided that if the 
heart sends out over two thousand tumblerfuls of blood 
every hour, and if the body holds no more than twenty- 
four tumblerfuls, — that is, six quarts, — the enormous 
supply must be explained somehow. We of course know 
that the same blood is being pumped over and over 
again, and that this explains the quantity. But Harvey 
did not know this. He 
asked where it all came 

One sign after an- 
other led him to sus- 
pect that the veins 
might supply the ex- 
planation. He there- 
fore tested both veins 
and arteries, as we our- 
selves may do. 

The Use of Valves in the Veins. Draw up your sleeve, 
swing your arm round your head once or twice, let it hang 
by your side for a minute, and you will notice that some 
of the blood vessels appear as dark lines under the skin. 
Stroke these lines down towards the wrist. They are 
veins, and the little bunches which stand out show 
where the valves have caught the blood. These valves 
are on the inside lining of every vein, and they always 
open towards the heart. When blood in a vein flows 

A B 

Pocket Valves in the Veins 

A shows a vein slit lengthwise and laid open ; 

B shows a vein cut through lengthwise; 

C shows how a vein looks from the outside 

when its valves are filled with blood 


towards the heart, the valves He flat and smooth against 
the lining, and you would not suspect their presence. 
But try to drive that blood in the vein away from the 
heart, and quickly every valve is lifted so that it stands 
out like a little pouch and blocks 
the passage of the blood back- 
wards. The structure of the 
veins, therefore, helped Harvey 
on towards his next discovery. 

Experiments with the Blood 

Flow. Uncover your left arm and 

squeeze it with your right hand, 

stroking the arm hard upward 

towards the elbow to hasten the 

blood out of the veins. Now, as 

quickly as you can, tie a bandage 

tight about the arm just above 

the elbow. Within a few seconds 

notice how you feel, and notice 

the color of your hand. It is 

pale and grows cold. 

Arteries are buried deep. Veins are near the surface. 

Your bandage is therefore checking the flow in both 

sets of blood vessels, and because no blood can get into 

the forearm, the color of it stays about as it was after 

you had tied the bandage. Above the elbow, however, 

you feel a throbbing, because the blood in the arteries 

A Handkekchief 
Stick to compri 




is held back by the dam of the bandage. Loosen the 
bandage a little. You have now lifted the pressure 
from the arteries, and blood hurries towards the hand. 
But the veins are under pressure still ; notice what is 
happening. Blood is enter- 
ing through the arteries; it 
cannot escape through the 
veins because of the pressure 
of the bandage. As a result ^ 
the hand grows red and swol- 
len from its unusual supply. 
Release the bandage entirely, 
and in almost no time the 
veins will have relieved them- 
selves. Blood is once more 
streaming upwards. 

Such experiments as these 
and others led Harvey to his 
second announcement. He 
declared to his astonished 
friends that the heart receives its entire blood supply from 
the veins. 

The Structure of the Heart. To complete this account, 
turn to the heart again and remember the following 
facts about it: 

I. The heart is a powerful muscle. It does its 
work by contracting and relaxing. When it relaxes, 

The Right Auricle and 

Ai vein that brings blood to the auri- 
cle ; B^ auricle ; C, valves that are 
forced open by the blood as it passes 
into the ventricle ; /?, ventricle ; E^ 
tube through which blood goes to 
the lungs to be purified 


the blood pours into it through an open valve; 
when it contracts, it forces about half a teacup of 
blood at a time onward and out of it through an- 
other open valve. Each time it contracts, its apex 
touches the wall of the chest near the fifth rib* 
This is what we feel and call the heart beat. After 

Two Views of the same Ventricle to show the Valves 

On the left blood enters ; on the right the ventricle contracts 

and forces the blood onward 

each of these beats, the heart relaxes and rests while 
more blood pours into it. We see from this that 
the heart rests about half the time. 

2. The heart is made up of two halves, and the 
wall of muscle between these separate halves is so 
firmly closed that after birth, and after the heart 
is in good working order, not a drop of blood ever 
passes through it from one side to the other. 


3. Each half of the heart has two divisions, the 
smaller called the auricle, the larger called the 

4. Each auricle and each ventricle has its own 
opening, its own tube for blood, and its own valves 
to prevent the blood from running the wrong way. 

5. The auricle in each half of the heart always re- 
ceives the blood and sends it into its own ventricle. 

6. Each ventricle receives blood from its own 
auricle and sends it off to its own district of the 

7. Tubes which carry blood from the heart are 
called arteries. Tubes which csLvry blood to the 
heart are called veins. 

8. The right side of the heart receives impure 
blood from the body and sends it to the lungs to be 
purified. This is called the pulmonary circulation. 
The left side of the heart receives the cleaned, 
purified blood from the lungs and sends it off 
through a large artery, the aorta, for use everywhere 
in the body. This is called the systemic circulation. 

The Double Work of the Heart. At this point we reach 
a most interesting fact about the process of circulation, 
yet it may be given in a few easy words. O^ie side of 
the heart always receives blood from the body and se7ids it 
to the lungs ; the otlier side of the heart always receives 
blood from the lungs afid sends it through the body. 


We see, then, that one side deals with pure blood alone, 
for all that comes to it is fresh from the lungs and 
is sent onward in the same condition; while the other 
side deals with impure blood 
alone, for all that comes to 
it has been used by the 
body and in this condition 
goes direct to the lungs to 
be purified. 

Thus the entire blood sup- 
ply of the body, on each Jour- 
ney round, passes through 
both sides of the heart and 
through the lungs before it 
goes back to nourish the body. 
This was Harvey's great dis- 
covery about the circulation 
of the blood. Even for him, 
however, there was still a 
mystery. " What becomes of 
the blood between times?" he 
asked. "How does it get from 
the arteries to the veins for its 
journey back to the heart ? " 
Capillary Connections. Harvey himself was not able 
to answer these questions, for microscopes had not yet 
been invented, and nothing but the microscope can 

The Four Cavities o 

The dark side receives impure blood 
from the body and sends it lo the 
lungs; the light aide receives pure 
blood from the lungs and sends it 
to the body 


reveal the close network of capillary connections which 
carries the blood across from arteries to veins for the 
return trip to the heart. 

The Circulatory System. But when the microscope 
came with its revelations, doubts and questions were 
cleared away. Instead of blood spread about everywhere 
among the muscles, under the skin, between the arteries 
and the veins, there was found to be no blood anywhere 
outside of the tubes. Moreover, each drop of blood was 
found to be a part of the ceaseless stream which flows 
through tubes that divide and subdivide until they are 
too small for the unaided eye to see, and then unite and 
continue to unite until they are again large enough to 
be seen. This is well called the circulatory system, for 
round and round the blood goes in endless circulation ; 
and when the circulating stops, we stop living. 

The following table shows how long it takes blood to 
make the entire circuit of the body in different animals.-^ 

Horse 25 seconds 

Full-grown man 23 seconds 

Child of fourteen 18 seconds 

Child of three 15 seconds 

Thus swiftly does the blood within us stream from 
the heart through arteries, capillaries, and veins, back 

1 A trained person pricks some harmless chemical into a vein on one side of 
the body, then examines blood from the corresponding vein on the opposite side 
•of the body until the same chemical appears there. By this he learns how long 
at takes blood to make the circuit. 

Vecns and Arteries 

Black tubes represent veins through which impure blood goes to the right side 

of the heart from all parts of the body; light-colored tubes represent arteries 

through which pure blood from the left side of the heart goes to all parts of the 

body. Notice that the large tubes of each kind lie near one another 



to the heart again. And the sight of its progress 
through the tubes must have thrilled those who watched 
it for the first time. 

Corpuscles in the Capillaries. One early scientist, who 
lived over two hundred years ago, looked through his 
crude microscope at 
the tail of a tadpole. 
He had already dis- 
covered the corpus- 
cles of the blood, 
which we shall study 
soon, and he saw 
these separate "blood 
globules," as he 
called them, moving 
after each other in 
single file through 
the narrowest of the 

tubes. Sometimes union of arteries and veins 

theymoved in faster, a. artery; v, 
sometimes in slower, 
procession; and sometimes they were even bent over 
and pressed out of shape as they were forced through 
the narrowest places. He grew enthusiastic over what 
he saw, and wrote a glowing account of it. 

The motion of the blood in these tadpoles exceeds all the rest of small 
animals and fish I have ever seen ; nay this pleasure has ofttimes been 


so recreating to me that I do not believe that all the pleasures of foun- 
tains and waterworks, either natural or made by art, could have pleased 
my sight so well. And now at last I spied a small artery, that notwith- 
standing it is so small that, I judge, but one small red globule of blood 
could pass through It, . . . yet, what was most remarkable was to see 
the manifold small arteries that came forth from the great one, and which 
were spread into several branches, and turning, came into one again, and 
were reunited, that at last they did pour out the blood again into the 
great vein ; this last was a sight that 
would amaze any eye that was greedy 
of knowledge. 

From what we saw, and from 
what we may see for ourselves 
with the microscope, we find 
it easy to understand that every 
gash made in the flesh of the 

Corpuscles in the Capillaries )^^y (,^^5 through a mesh of 
OF A Frog's Foot ■' '=' 

lacework more dehcate than 

the finest lace ever made by the hand of man ; we see 
that each thread of this lace is a tube doing faithful duty 
in carrying blood to remote regions of the body ; we see 
that everywhere there is blood simply because every- 
where there is the same intricate interlacing of these 
marvelous tubes. Their name capillary vataxi.?. "hairlike." 
Yet the microscope shows how much smaller they some- 
times are than any human hair, however soft and fine. 

By careful calculation it has been found that fifteen 
hundred capillaries would have to be laid side by side 
to cover a surface an inch wide. 

The Heart with its System of Tubes 

Arrows show the direction in which the blood flows. Follow its course from the 

body into the right side of the heart ; from there to the lungs ; thence to the left 

side of the heart and out to the body again. Each cluster of tubes shows in a 

rough way where some organ of the body is located 



The Blood Supply. As a rule, the amount of blood 
which is inclosed in the system of tubes which includes 
heart, arteries, capillaries, and veins is about one thir- 
teenth the weight of the person. We may then calculate 
our own supply of blood by our own weight, and decide 
just how much it takes to keep our blood vessels and 
heart as full as they need to be. The truth, however, 
is that being elastic they could at any time hold 
more than is now in them; and that at any time also 
they could get along very well with less than they 
now carry. 

In former times men sometimes died for no other rea- 
son than that they lost so much blood from wounds of 
one sort or another that the sides of veins and capil- 
laries collapsed, and the heart had to stop work because 
there was too little blood left in the body to be pumped 
round. It was therefore a great discovery when men 
found that the heart is quite as willing to pump warm 
salt water out into arteries and capillaries as to send 
warm blood to the same places. Nowadays, therefore^ 
when a man is losing much blood through an operation 
or through an accidental wound, a surgeon, working as 
fast as he can, pumps salt water into the veins to replace 
the blood. This water is carried on round the circuit as 
swiftly as if it were the richest blood, the pumping of 
the heart continues, and a life is saved. It keeps the 
veins filled and the heart in action for a season, while 


the proper sort of blood is being manufactured by the 
body itself. 

Exercise and the Blood Supply. In a way we might 
suppose that the blood of the body is spread out in equal 
quantities everywhere, being regulated by the size of the 
tubes which carry it about. The truth is, however, that 
exercise regulates the amount of blood which goes here or 
there ; that is, what we do always settles the question as 
to where the blood shall go. For the normal healthy per- 
son this law never varies. It may be stated in a few 
words : that part of the body which is exercised the most 
gets the most blood ; that part which is exercised the least 
gets the least blood. 

The sixth chapter shows what it means to the body 
when this law is remembered or forgotten, and what the 
nature of the blood is, that it should be so greatly 
needed here and there. But before taking up that sub- 
ject, we turn to the study of heart action and nicotine. 


1. How may you get the standard of your heart beat? 2. What 
shows the rate of heart beat, and how can you increase that rate? 

3. Which increases heart beat more, exercise of large or of small muscles? 

4. Why does a doctor feel the pulse of his patient? 6. Give two op- 
posite mistakes often made in exercising the heart 6. Describe the 
heart — its structure, position, and size. 7. When does it work? 

8. How may the heart of a tennis player show that it is overtaxed ? 

9. How should one begin tennis-playing in the spring? 10. Mention 


some way by which muscles, heart, and breathing apparatus can all be 
trained at the same time. 11. What advantage is there in having a 
well-trained heart ? 

12. Who was William Harvey? 13. What did he notice about the 
flow of blood from different wounds ? 14. What, was Harvey's first 
great discovery? 16. Give some facts that led him to this discovery. 
16. How many quarts of blood are there in the body ? 17. How much 
blood does the heart send out each time it contracts ? 18. How often 
does it contract each minute ? 19. What are the pockets in the veins ? 
20. Which are deeper in the body, arteries or veins? 21. What does 
the experiment with the bandage above the elbow prove? 22. What 
was Harvey's second discovery? 23. What can you say about the 
two halves of the heart? 24. What is the work of the auricle? the 
ventricle ? the arteries ? the veins ? 25. What is the aorta ? 26. Which 
side of the heart receives impure blood from the body and sends it to 
the lungs to be purified? 27. Which side receives pure blood from the 
lungs and sends it to the whole body to be used ? 

28. How long does it take blood to make the circuit of the body for 
a man ? for a child of fourteen ? 29. Describe the circuit of the blood 
from the veins back to the veins. 30. How does the blood get from 
the arteries to the veins for its return journey to the heart? 31. When 
you cut yourself and blood flows, what have you actually done? 
32. What does capillary mean? 33. What can you say about the 
amount of blood which the blood vessels may hold? 34. In what 
way is warm salt water sometimes useful in blood vessels ? 35. What 
connection is there between exercise and the amount of blood sent 
to different parts of the body? 36. Give this law of exercise. 



Tests with the Sphygmograph. In some tests which 
he was making, Dr. McKeever^ enlisted the help of over 
one hundred boys. Their ages ranged from twelve to 
twenty years, and they all smoked. Indeed it was just 
because they smoked that Dr. McKeever was making 
his tests. He wished to see for himself what tobacco 
does for boys. If it helps them either in body or in 
mind, he intended to pass the fact on for the benefit 
of other boys. 

In carrying on his investigations Dr. McKeever used 
the sphygmograph. This machine has a clockwork con- 
trivance which moves a strip of smoked paper on which 
a needle records the heart beat. It is fastened to the 
wrist directly over the artery which passes that way, 
and as the artery throbs with the beating of the heart, 
the needle of the sphygmograph traces its way across 
the smoked paper and leaves its scientifically exact 
record there, in black and white. The illustration on 
the next page shows the making of a record. 

^ Dr. William A. McKeever, Professor of Child Welfare, The University 
of Kansas. 



The boys were interested in the way the machine 
worked and in what it told about their heart action 
before and after smoking. 

General Effects of SmoklDg. The records were taken at 
different times during the year, and each was slightly 
different from all the others, just as the handwriting 

The Sphvgmugrafh on a Wkist, and the Klcord it is making 

of one person always differs from that of another. On 
the whole, however, the various reports of the sphyg- 
mograph explained two apparently contradictory facts, 
both of which are perfectly well known: 

1. The smoker says he feels better and is able to 

think faster and to work harder just after smoking 

than before the smoking. 


2. Athletic coaches say tobacco prevents success. 
They therefore prohibit its use by their men. 

It is as if one honest man said, " Smoking does me 
good," while another man, equally honest, says posi- 
tively, " Smoking does you harm." 

To reconcile these differences we turn to the dia- 
grams borrowed from Dr. McKeever's record. Notice 
that one of these shows the heart beat of a tired young 
woman. She did not smoke, but she was on the verge 
of nervous prostration. Compare this with the record 

Sphygmograph Record of the Heart Beat of a Young Woman on 

THE Verge of Nervous Prostration 

The young woman does not smoke. (From Dr. McKeever) 

of the vigorous young fellow of nineteen who did not 
smoke. It shows the kind of work a healthy boy's 
healthy heart should do for him. (See p. 76.) 

Compare both these records with the wave lines in 
the third diagram — the one on page "]"]. See that first 
flattened-out report (i), taken before the smoking began. 
It is quite like the heart beat of the worn-out young 
woman — faint, weak, lifeless. No wonder the fellow 
felt dull ! 

Effect of Smoking on the Heart. Study the next report 
from the same person. See the beat bound upward 



when the smoking begins — stronger, faster, more vigor- 
ous. Fresh blood is being sent to every part of the 
body. The brain feels it first and becomes more active. 
The smoker says he " feels good " — and no wonder. 
Not brain alone, but muscles and liver, stomach and 
lungs and kidneys, are now getting better blood faster 
and in larger quantity. Even the farthest-off, smallest 

Sphygmograph Records of the Normal Heart 

I, tracing for a vigorous fellow of nineteen; does not smoke. 2, healthy heart 
beat ; a calm temperament ; does not smoke. 3, heart tracing for a healthy young 

woman; does not smoke. (From Dr. McKeever) 

capillary is stretched out a little larger, and more blood 
than usual hurries through it for a few minutes. 

But this flush time is soon over. Fifteen minutes 
have passed. The sphygmograph has not been taken 
from the wrist; it is still making records. And now 
see what has happened. All the splendid vigor has 
faded out. Once again the heart beats almost at dead 
level. Brain cells lose their activity; muscles and liver, 
stomach, lungs, and kidneys, have to do the best they 



can with the slow-moving blood. It brings short^.rations 
of food to cells that cry out for nourishment. But, sad 
to say, the slow-pumping heart will stay in charge of the 

Sphygmograph Records of the Heart Beat of Two 

Different Persons 

I, 2, 3, tracings made by the heart of a young man of nineteen : i, before smok- 
ing; 2, while smoking; 3, after smoking. He began to smoke cigarettes at 
fifteen. 4, 5, 6, tracings made by the heart of a young man of twenty : 4, before 
smoking ; 5, while smoking ; 6, after smoking. Began smoking at thirteen ; now 

uses a strong pipe. (From Dr. McKeever) 

slow-moving blood until the next cigarette is smoked. 
Then it will jump into quick action again for a few 


The Tobacco Heart. This is why a smoker must often 
use fifty and sixty cigarettes a day to keep his heart 
up to the mark. This is how a healthy heart gets 
turned into a weakened heart. This is why the steady 
smoker often fails where he wishes to succeed. And 
the real reason for all this is the double character of 
tobacco; it is a stimulant, and it is also a narcotic 
poison. The smoker craves the stimulation ; in addition 
he receives the poison of nicotine. 

How Nicotine gets to the Heart. When a man lights 
his cigarette, the woody fiber of the burning tobacco 
turns to smoke and ashes, and at the same time the 
nicotine turns into vapor. If now the man draws the 
smoke into his lungs, the vaporized nicotine goes with 
it. But after reaching the lungs they separate. The 
smoke stays on all the delicate tissues of the lung cells, 
which is bad enough, but the vapor of the nicotine is 
not hindered by any tissues. Instead it passes directly 
through the tissue of the lung cells, enters the blood 
stream, and is whirled to the heart by the straightest 
road possible. 

Effect of Nicotine on the Heart. At the moment it ar- 
rives, the sphygmograph shows what the poisoned whip 
has done. It has lashed the heart to vigorous action — 
not to last long, however, for soon the same sphyg- 
mograph shows that the vigor has gone, and that the 
permanent condition grows worse rather than better. 


The United States army gives proof of this. At an 
examination for the military school at West Point, one 
quarter of the young men had to be refused admittance 
because they brought upon themselves the condition of 
" tobacco heart " from cigarette smoking. 

At another time a set of 412 boys wished to enter the 
naval school at Annapolis. They were examined by an 
officer in Peoria, Illinois, and all but 14 were turned 
away. As was said by the examiner, '* Of the 398 re- 
jections, the greater number were on account of weak 
hearts, and in the majority of cases this was caused by 
cigarette smoking." 

Dr. Seaver^s Tests. In 1897, at Yale University, when 
Dr. Seaver made his thorough study of the matter, he 
found that out of every 100 students who ranked high- 
est, 5 were smokers, 95 nonsmokers. Among the rest of 
the students at that time, 60 out of every 100 smoked. 
He also found that, on the average, those who did not 
smoke gained more in height and weight and girth of 
chest than those who smoked. 

Remember that these Yale students were still in the 
growing time of life ; recall the facts of the last chapter ; 
then imagine what it means to have a young and grow- 
ing heart attacked over and over again, day in and day 
out, for weeks and months and years, by a poison that 
does its worst work with the heart itself. It seems as if 
no harm to the heart could be much more serious. 


Army officers and doctors declare that he who is in 
the habit of using cigarettes should be careful riot to do 
anything that will call for sudden, or violent, or vigorous 
use of muscles and heart. Although he may still be able 
to run as fast and to jump as high as his friend or his 
schoolmate who does not smoke, yet the probability is 
that he has the sort of heart that the army refuses to 
accept — the heart that no soldier can afford to own. 
And the man who is afflicted in this way cannot expect 
to excel on the athletic field. 

In this connection it is interesting to know what 
the leading trainers of the country say about the use 
of tobacco. 

Mr. Mc Bride, once captain of the Yale football team, 
wrote : 

It is absolutely necessary for a college or school athlete who is striv- 
ing to win a place on any team to have endurance; especially is this 
true in rowing and football. This can be accomplished to the greatest 
degree only by abstaining from the use of tobacco and alcoholic drinks 
while in training for said team. 

Mr. Edwards, once captain of the Princeton football 
team, wrote : 

A man who is using tobacco and alcohol contrary to orders during 
the season is easily detected, and is dropped from the squad. 

Mr. A. A. Stagg of The University of Chicago wrote: 

We have never had a really successful long-distance runner at The 
University of Chicago who was a smoker. In football, as in other 


endurance tests, there is no question at all in my mind that the man 
who smokes does not come up to the level of the general nm of 

For thirty years " Mike " Donovan was the athletic 
director of the New York Athletic Club, and from his 
wide experience he writes: 

Any boy who smokes can never hope to succeed in any line of 
endeavor, as smoking weakens the heart and lungs, ruins the stomach, 
and affects the entire nervous system. If a boy or a young man expects 
to amount to anything in athletics, he must let smoking and all kinds of 
liquor alone. They are rank poison to his athletic ambitions. 

It would seem then that, for the sake of the heart and 
for the sake of success, cigarettes must be put aside. 
And now we return to the subject of circulation and 
the blood stream. 


1. Describe Dr. McKeever's tests with the sphygmograph. 2. Describe 
the sphygmograph. 3. Give the two opposite statements made by 
smokers and by athletic coaches. 4. Show by the chart why the smoker 
feels so well just after smoking. 5. What happens to the heart soon 
after the smoking stops? 6. Why are many cigarettes necessary to 
make one feel vigorous ? 7. What objection is there to these cigarettes ? 
8. How does nicotine get to the heart ? 9. What effect does it have ? 
10. Why are so many boys rejected by the medical examiners for West 
Point and Annapolis? 11. Describe Dr. Seaver's tests with college 
boys. 12. What did he discover about their scholarship ? about their 
height, weight, and girth of chest? 13. If a person is in the habit of 
using cigarettes, what kinds of exercise must he avoid ? 14. What have 
some of the athletic directors and football men said about the effect of 
tobacco on health ? 



Blood Examination. Tie a string round the last joint 
of a finger of your left hand. Bend the tied finger over, 
to increase the pressure of 
the blood in its capillaries. 
Take the finest needle you 
have, hold it in a candle or 
a lamp flame for a moment 
to rid it of microbes, then 
stick the point of it quickly 
into the dark-red end of the 
finger. You will tear open 
several capillaries smaller 
than the needle, and a good- 
sized drop will ooze through. 
Nevertheless you will barely 
feel the prick. Have a 
°^ piece of clean glass ready 
and jostle the drop of blood 
down upon it. Raise the glass, hold it over something 
white, and notice the color. You will see that it has a 
yellow tinge. Leave it on the glass for five or six 



minutes, then look at it again. You will find it turned 
to jelly. Set a tumbler over it and let it remain undis- 
turbed for half an hour or so. At the end of that time 
you will see a bit of red substance floating in a small 
drop of liquid which is 
almost colorless. 

Coagulation. Lookback 
at the finger you pricked, 
and if you did not wipe 
it off clean after you 
did the pricking, you will 
see that there, too, a rem- 
nant of the blood has 
hardened round the edges 
of the tiny wound. This 
hardening of part of the 
blood is called coagula- 
tion. It will remind you 
of the statement so often 
made, that the best healer 
for a wound is the blood 
which oozes through it. Healing goes on beneath it. 

Blood under the Microscope. If we could add the use 
of a microscope to our experiments, we would draw a 
second drop of blood, and we should learn a number 
of important facts about its composition. We should 
then recognize it as a liquid with multitudes of small 

Corpuscles seen by the Aid of a 

A few red ones are highly magnified. 
Those that are less magnified show how 
corpuscles stick together after blood is 
drawn from the body. Two white corpus- 
cles are given 


red and white objects floating in it. Blood is indeed 
a mixture of three things: 

1. Red objects^ called red corpuscles^ which give the 
blood its color. There are millions of these in each 
drop of healthy blood. Imagine then their size! 
Each is round and flat, with a concave center, and 
these microscopic disks are the important oxygen 
carriers of the body. They never leave the blood 
tubes unless these tubes themselves are crushed, or 
cut, or forced to leak through accident or disease. 

It has been estimated that the life period of a red 
corpuscle is about six weeks, that there are perhaps 
twenty-five millions of millions of them in the blood 
of the average man, that seven millions die with 
each tick of the clock, and that during the same 
clock tick seven other millions are created by the 
body to replace them. Do not try to memorize 
these figures. They are stated here just to give a 
notion of the vast numbers of the blood corpuscles. 

2. The liquid part^ called plasma. This is quite 
transparent and almost colorless. A little over one 
half of each quart of blood is plasma; the rest is 
the corpuscles. 

3. Colorless objects^ called white corpuscles. Of 
these there are usually from five to seven thousand 
in each cubic millimeter,^ although the number 

1 Fifty cubic millimeters make a drop of water. 



varies from time to time. White corpuscles are 
specks of living, jellylike substance which change 
their shape constantly. They not only travel with 
the other corpuscles in the plasma, but they also 
work their way through the walls of the capillaries 
and wander here and there in the body. They are 
soldiers and scaven- 


gers too, for, as the 

last chapter of this 

book shows, they not 

only destroy harmful 

microbes when they 

find them, but also 

help more than any 

other part of the blood 

in healing a wound. 
The Blood's Important 
Work. Plasma, red corpus- 
cles, and white corpuscles 
are all that the microscope 

shows when we use it for the study of blood. But a 
chemist will take the same blood, analyze it in his labo- 
ratory, and prove that it is made up of many different 
substances of which we have not so much as heard the 
names — substances needed, however, for the work which 
each separate part of the body is doing. He will tell 
us that within the blood is all that is needed for the 

Red and White Corpuscles 

Four different shapes and four positions 
taken by the same white corpuscle 


manufacture of bone, muscle, hair, tendons, tears, fat, and 
finger nails; that it is the source of supply for all that 
Hes under the cover of the skin, the storehouse for more 
treasures than we have even dreamed about; and that it 
is easy to enrich or to impoverish the blood by our 
treatment of the body. It is, indeed, for the benefit of 
the blood that food and air do the important work which 
will be studied later. 

But the question is. How can 
blood do so much when it stays 
all the time within the confines 
of the tubes? Nothing but an 
experiment can clearly answer 
this question, and we can make 
„ „ this for ourselves. 

One Glass within the 

Other Exchanges along the Tubes. Get 

The smaller glass holds fresh from the butchet 3. piccc of fresh 

water, the larger holds water . , , i i i . -n 

and salt animal membrane — a bladder will 

do. Fill a small glass with fresh 
water, tie the membrane tightly over it, set the glass 
into a much larger one filled with salted water, letting 
the water cover it, and leave the two glasses together 
overnight In the morning take out the smaller 
glass, unfasten the membrane, and taste the water 
which was fresh and sweet the night before. You will 
find that it is now distinctly salt. Taste the water in the 
larger glass. You will find that it has grown fresher. 


In this exchange the salt in the Hquid has acted 
according to a universal law. Salt is indeed one of 
the many substances which pass easily back and forth 
through any moist animal membrane. This process is 
called osmosis. 

Put sugar into one glass of water and soda into 
another. Let a membrane be stretched between them, 
as was done in the fresh-and-salt-water experiment, and 
before long you will have two liquids that have become 
strangely alike. The different substances in the solutions 
have changed places through the membrane, according 
to the law of osmosis. 

Gas Exchanges in the Blood. Even gases are subject 
to the same law. Men who know how to handle such 
things can put oxygen in one tube and carbon dioxide 
in another. They can then separate the gases by a 
piece of animal membrane stretched between the tubes, 
and they discover that the two gases refuse to stay apart. 
Indeed so much of each finds its way through the par- 
tition that soon there is a mixture of the two on either 
side of the membrane. 

Experiments such as these answer the query as to 
how the body gets what it needs from the blood. Every- 
where it is the animal membrane of the tubes themselves 
which separates the blood within the tubes from a cer- 
tain other liquid which lies close about them on the 


Lymph and Oxidation. However small and however 
thin-walled the blood vessels may be, there is always 
this clear liquid, called lymph, bathing the outside of the 
capillaries like a sort of colorless sap in the body and 
making its exchanges with the contents of the liquid 
within the hairlike tubes. Moreover, this lymph, which 
soaks slowly but constantly through every tissue of the 
body, is laden with carbon dioxide, which it has received 
from the tissues themselves. The blood is rich in oxy- 
gen, and it is separated from the lymph only by the walls 
of the capillaries. In view of this, what could be more 
natural than the thing which comes to pass ? The gases 
in the lymph and in the blood change places with each 
other as promptly as do the liquid materials which are 
also in the lymph and in the blood. And this exchange 
is part of the great process known as the oxidation of 
the blood. 

It is evident, then, that lymph is as important to us 
as is blood itself. In fact, the two must always travel 
side by side. They are indispensable to each other. 
Without the one the other is useless. Three statements 
will show how close the relation is : 

I. Blood in the arteries is the result of the food 
we eat and of the air we breathe. It contains every 
supply that any part of the body needs for nourish- 
ment, for strength, and for growth, and it is sent 
here and there by the action of the heart. 


2. Blood in the veins is what is left after the 
lymph has taken from it the oxygen and other 
nourishment which the body needs, and given in 
exchange the carbon dioxide and other waste which 
must be carried off. In other words, venous blood 
contains much waste from the tissues and little 
nourishment for the tissues; while arterial blood 
is rich in nourishment for the tissues and contains 
little waste. 

3. Lymph is made up of rich nourishing plasma 
derived from the blood, on its way to the tissues, and 
of waste material from the body, which will soon 
pass into the capillaries, be carried onward in the 
veins, and be disposed of as we shall learn hereafter. 
Lymph is also the highroad to the blood for many 
substances that are being manufactured by differ- 
ent organs of the body. These manufactured arti- 
cles must find their way into the blood, for only 
through circulation will they ever be able to reach 
their destination. 

The Lymphatic System. The origin of the lymphatic 
tubes is strangely interesting for the simple reason that 
it is so very indefinite. Each seems to begin about as 
irregularly as a stream that gathers water in a swamp. 

As we know, blood vessels are a closed system of 
tubes with a stream of blood sweeping through them 
endlessly — going ever round and round, from the heart 


through the arteries, the capillaries, and the veins, back to 
the heart again. In this great system not even the small- 
est tube in the remotest region of the body is left with 
an open mouth. The lymphatic system, however, works 
on quite a different basis. Here the vast multitudes of 

Look for those with open mouths ; A, artery ; V, vein ; L, L, L, lymphatics 

the smallest tubes seem to be really little more than 
open mouths Into which liquid is gradually making its 
way. Bear this in mind while the facts are given as 
definite statements: 

I. Each blood vessel of the body makes its way 
through a meshwork of tissues. 


2. Everywhere among these intertwined tissues 
there is a colorless liquid called lymph. The capil- 
laries of the blood are surrounded by this lymph, 
just as grass and weeds are surrounded by water in 
a swamp. Lymph looks 

like the plasma of the 

3. Lymph and plasma ' 
are constantly making 

exchanges through the 
walls of the blood vessels. 

4. Plasma is getting 
from the lymph all that 

, the body is through with 
— all that should go on 
in the blood and be dis- 
posed of elsewhere. 

5. Lymph is getting 
from the plasma all the 

nourishment which the lvmphatics of the Hand 

tissues need Smaller tubes lie near the surface, 

larger ones lie deeper 

6. Openmg away from 

the loose fibers through which the blood vessels run, 
and in which all this exchange is going on, there 
are other tubes about as small as the capillaries; 
and into the open mouths of these tubes the lymph 
from the tissues gradually makes its way. 


7. Vigorous exercise hastens the flow of lymph 
no less than of blood, and the tissues are benefited 

8. From start to finish 
the lymphatic tubes, like 
the veins, progress in size 
from smaller to larger. 
They are also provided 
with inside pockets quite 
like those of the veins. 
These pocket valves keep 
the lymph from moving 
backward and help to send 
it constantly onward, that 
it may at last mingle with 
the great stream of blood 
that goes to the heart. 

g. This progress from 
smaller to larger tubes con- 
tinues until all the lymph 
of the body finds its way 
into two large lymph tubes, 
one on each side of the 
neck. These empty into 

two large veins, and thence- 

Veins and Lymph Tubes , , , , 1111 

forward lymph and blood 

The lymph tubesare white andare , . , 

seen W empty into the large veins gO on their way together 


to the heart. The lymph, with all it has gathered, 
has now entered the circulatory system, and thus 
the contributions from the many different organs 
of the body will be distributed by means of the 
blood. The movement of this fluid continues dur- 
ing life, for the lymph vessels and lymph spaces 
can never be empty as long as the organs of the 
body are at work. 
A special point to remember is that blood vessels 
and tissues are as much better off when fresh lymph 
surrounds them as ar^ fish when they are in fresh water. 
The next chapter shows what happens when alcohol 
enters the streams of blood and lymph. 


1. How would you get a drop of blood for examination ? 2. What 
is the color of the blood? 3. How do you know that blood hardens 
soon after it leaves the body? 4. What becomes of it after it has 
been left standing about half an hour? 5. What is coagulation? 
6. Of what value is coagulation in healing a wound? 7. What three 
things mixed together form blood ? 8. Describe red corpuscles ; white 
corpuscles. 9. What is the liquid part of blood called ? 10. What can 
a chemist find out about blood? 

11. Describe experiments which prove that certain substances can 
pass through a moist animal membrane. 12. What is this process 
called? 13. What exchange of liquids and gases in the body is ex- 
plained by these experiments? 14. What is lymph like, and where is 
it found ? 15. What gas passes from the tissues of the body into the 
lymph? 16. How does it reach the red corpuscles? 17. How does 


oxygen from the red corpuscles get to the tissues? 18. Which two 
gases change places in the red corpuscles? 

19. Describe the blood in the arteries. 20. Describe the blood in 
the veins. 21. Describe the origin of the lymphatic tubes. 22. What is 
the difference between the system of blood vessels and the system of 
lymphatic tubes? 23. What does lymph look like? 24. What does 
plasma receive from lymph ? 26. What does lymph receive from 
plasma? 26. Of what use are the pocket valves in the lining of the 
lymph tubes ? 27. How does vigorous exercise help the body through 
the lymph ? 28. Why is it well for tissues to be surrounded by fresh 
lymph ? 



Slow Circulation of the Blood. Red eyelids and a 
pink nose tell plain facts about the state of the capil- 
laries in those particular regions, but the mere fact 
that a man has a red nose signifies very little about 
his general health. Many a hearty sea captain has 
carried such a nose with him through half a century. 
He has lived to be eighty years old or older, and the 
shade of his sunburned nose has mattered little to him. 

Sometimes, however, the color of a man's nose is a 
sign of general internal conditions. It may show that 
the capillaries throughout his body are loaded with 
slow-moving blood, and this condition of the capillaries 
throws a flood of light on the sort of work which the 
heart itself is doing. 

Judging by facts which we have already learned, 
three points are clear: 

I. Slow-moving blood is more impure than fast- 
moving blood. For this reason such blood is always 
a disadvantage to any part of the body in which 
it tarries. 



2. The mere fact that blood is moving fast shows 
that impurities are being hastened out of the way 
and that fresh material is being supplied to lymph 
and tissue. 

3. The blood vessels must always be in a healthy, 
vigorous, elastic condition if the best exchanges are 
to be made through their walls. 

Alcohol and the Heart Beat. In view of these state- 
ments we are ready to understand a set of discoveries 
about circulation which have been made during the past 
few years. It appears that for many previous years 
educated doctors and ignorant men alike believed that 
alcohol was a genuine help to the vigor of the circula- 
tion. Thousands of men thought they had proved this 
by personal experience. At different times, and in dif- 
ferent places, they had taken alcohol in large doses or 
in small doses, and after the drinking they had tested 
their hearts and found by counting the pulse that the 
number of heart beats had increased. They had felt the 
pleasurable effect of blood bounding faster through their 
veins, and it was most natural for them to believe that 
the alcohol which they had taken had strengthened the 
heart, just as food strengthens the body. 

Testing the Heart Beat with the Sphygmograph. In 
time, however, came the sphygmograph, with its tests of 
vigorous and languid hearts. It is in wide use to-day, 
because doctors find that they can judge in a general 


way as to whether a man is well or not by the vigor or 
the languor with which his heart does its work. 

Doctors and teachers alike were now astonished. 
They took alcohol themselves; they gave it to their 
friends and their patients; they studied the heart and 
found that its throbs had increased in number. But 
when, in this condition, they used the sphygmograph, 
they were surprised to see that the heart was not put- 
ting as much power into each stroke after the alcohol 
was taken as it had done before. 

Alcohol and Heart Vigor. Over and over again the tests 
were made, with the same result. Each trial showed that 
although the heart was pumping faster than usual, it was 
nevertheless doing its work with less vigor. It was using 
less force for the increased number of strokes than it 
had used for the smaller number made before alcohol 
had been taken into the blood. 

Testimony of this sort gave a new color to the practice 
of- using alcohol when the heart needs to be strength- 
ened. Doctors in every land had to yield to the evi- 
dence of their senses. They had to believe that, instead 
of giving strength, alcohol actually robs the heart of a 
part of the strength which it had before the alcohol was 
taken. This was a hard thing to believe, yet to-day the 
facts of the case are accepted by all up-to-date, intelligent 
people. And this is why our best doctors are giving so 
much less alcohol nowadays than in former times. 


First Effects of Alcohol. Here are a few of the most im- 
portant points about the eflfects of alcohol on the body : 

1. Healthy tubes that carry blood are elastic. 
They stretch out when blood is pumped into them 
by the heart, and they contract firmly again as 
they send the blood onward. 

2. The first eflfect of alcohol in the body is to 
paralyze in a very slight way ever}' tube that has 
anything to do with cany-ing blood hither and 
thither. This means that alcohol is a narcotic and 
not a stimulant^ 

3. Because the tubes are slightly paralyzed they 
are more relaxed than formerly. They contract less. 
They therefore offer less resistance to the blood 
that is pumped into them. After they are full they 
stay relaxed and do not have the elastic power to 
pull themselves firmly into shape again. 

4. The heart is also slightly paralyzed by the 
alcohol. Still, those countless relaxed tubes offer so 
little resistance that the heart pumps the blood 
into them with less effort than formerly, and, as a 
result, contracts more frequently. 

Thus far, however, no harm appears. The capillaries 
are full of blood ; the man feels the warmer for it, and 

* A narcotic is something that lowers the vitality of the body and may harm it. 
A stimulant is something that stirs even a tired organ or a tired body to activity. 
Certain stimulants are dangerous things to use. 


his heart is beating a trifle faster than usual. That is alL 
But now begins the chapter of damages and calamities. 

The Seal Harm of Alcohol. During the time that the 
heart itself is weakened, it cannot put force enough into 
each stroke to drive the blood on in spite of the relaxed 
state of the walls of the tubes. Various results now 
follow. Blood moves more slowly through the tubes; 
it is slow in carrjnng away broken-down tissue from 
the lymph; it is slow in bringing fresh nourishment 
for the rebuilding of the tissues. 

In the meantime, if alcohol continues to be taken, the 
capillaries may be kept stretched so long as to lose all 
power to contract If this state continues, the walls them- 
selves end by becoming thicker and stiffen The work of 
exchange which should go on at a rapid pace through 
them is thus interfered with, and the health of the 
drinker suffers in numerous ways. 

This is no fancy picture. It is simply the history of 
circulation in such persons as are ignorant enough to 
be willing to rob themselves of the service which their 
blood and their blood vessels should do for them. 

Fat about the Heart. The gravest aspect of the aflFair, 
however, is in connection with what happens to the 
heart Because this tireless pump is weaker than it 
was, it also becomes stretched; and as it cannot do 
full work, it lacks the exercise which would keep it in 
vigorous health. It grows flabby, as does an unused arm. 


Fat gathers not only between the fibers but also within 
the body of each separate fiber. In this latter case, fat 
takes the place of tissue itself, and then occurs what 
is called fatty degeneration of the heart' — a most seri- 
ous condition. For a heart of this sort is too weak to 
send blood onward as rapidly as it should go. This 

Two Hearts Side by Side 

On the left the heart is normal; on Che right it is enlarged and weakened by fat 

(Copied from Alcohol and the Human Body, by Horaley and Sturge) 

means that circulation throughout the entire body is 
hindered, and that each great organ suffers for lack 
of what it should get through fresh supplies of blood. 
Evidently, then, he who owns a fatty heart, weakened 
from any cause, is far less sure of continued life than 
he might have been. Since he secured this condition 
through ignorance, he is not to blame. But sad as is 


the fact, ignorance never saves men from the results 
of their ignorance. 

Weakened Heart and Arteries. Why do surgeons dread 
to do anything for the man who uses alcohol ? Because 
they know only too well that the power of his heart 
and the elasticity of his arteries have been so reduced 
that his heart may not rally after the operation. In 
writing of this danger, Sir Frederick Treves says: 

Having spent the greater part of my life in operating, I can assure 
you that there are some patients that I don't mind operating upon and 
some that I do; but the person of all others that I dread to see enter 
the operating theater is the drinker. He is the most dangerous feature 
in connection with the surgical life. 

It is because of this constant state of relaxed capil- 
laries that the nose of the drinker stays red. In his 
case the nose is frequently a reliable sign of internal 
conditions. Any man with weakened heart and arteries 
should have nothing to do with such running as is de- 
scribed in the next chapter. It may put his life in peril. 


1. When the nose or any other part of the body is red, what do 
we understand about the capillaries just there? 2. What objection is 
there to having blood move slowly through the capillaries ? 3. Mention 
two advantages that are connected with fast-moving blood. 4. Why 
should the walls of the blood vessels be kept healthy, vigorous, and 
elastic? 6. What did doctors formerly think about the connection 
between alcohol and circulation ? 6. After a man takes alcohol does his 


heart beat faster or slower? 7. What dees the sphygmograph show 
about the power of the heart before and after alcohol has been used ? 
S, Does this prove that the heart receives strength or is robbed of 
strength by the alcohol ? 9. What is the natural condition of the blood 
tubes? 10. Are they elastic or nonelastic? 11. What effect does 
alcohol have on them? 12. Why is this harmful? 13. What is a 
narcotic ? a stimulant ? 14. What effect has alcohol on the heart ? 
15. Describe the result when both blood tubes and heart are thus 
weakened. 16. What finally happens to the walls of the tubes? 
17. What effect does this have on the exchanges between plasma and 
lymph ? 18. Why does the body suffer when the exchanges are made 
slowly? 19. Describe the condition of the heart after it has been 
weakened by alcohol. 20. What objection is there to fat among the 
fibers of the heart? 21. Why do surgeons dread to operate on a man 
who uses alcohol? 


What is Breathlessness ? If you were ever thoroughly 
out of breath, recall the sensations you had at the time. 
Perhaps you were trying 
to catch a train ; perhaps 
you were running in a re- 
lay race. In either case 
you felt that you must 
reach the goal at all haz- 
ards, and you ran as you 
had never run before. 

Your breath came and 
went freely, and during 
the first few moments you 
drew deep, long breaths 
of equal length. Soon, 
however, you found that 
each breath was shorter „ „ „ 

Breathless at the End of the Race 
than the last. You began 

to be uncomfortable. There was a tight feeling within 

you, as if an iron band were closing itself about your 

chest; as if it prevented you from expanding your 


lungs to their full size. You wondered how much 
longer you could keep it up. 

But why were you breathless? To answer the ques- 
tion, follow once more the condition of muscle and 
bone, tendon and heart, lungs and blood vessels, while 

67 8 9 

Nine Views of the Same Man as he Ran 

A different set of muscles is at work in each position, so that altogether many 

muscles are used in running 

(After Schmidt) 

you were running. Think for a moment of your in- 
elastic tendons as they stayed firmly gripped to their 
bone attachments. Remember how each one of multi- 
tudes of muscles, large and small, shortened and length- 
ened as by means of their tendons they pulled those 
leg bones of yours up and down and kept them at 
work. Remember that neither arms, back, neck, nor any 
other part of your body was relaxed as you ran, but that 
every muscle seemed to work hard in keeping time and 


step with the movement of the legs. Remember that 
such violent action as this means that changes are 
going on in the substance of the living tissue which 
is exercised; that these changes involve the giving off 
of unusual quantities of carbon dioxide; that oxygen 
is needed by the working fibers; and that in order to 
supply the oxygen and to carry off the carbon dioxide 
and other waste products, fresh streams of blood must be 
hastened to the active muscles with ever-increasing speed. 
The most immediate, imperative need of each working 
fiber is to get rid of the excess of carbon dioxide. 

The Cause of Breathlessness. There are three things 
which bring about such a condition of breathlessness: 

1. Exercise violent enough to compel the fibers 
of the muscles to produce unusual quantities of 
carbon dioxide. As this gas is produced, oxygen is 
demanded by the fibers. It is, indeed, as if they 
themselves were breathing. 

2. The activity of the chest walls as they expel 
the carbon dioxide from the air sacs of the lungs 
and replace it with air containing oxygen. 

3. The rapid work of the heart as it receives 
larger amounts of impure blood than usual through 
the veins and sends arterial blood to the tissues to 
czrry oxygen and to bring away carbon dioxide. 
To a large extent it is this forced work of the 
heart that explains the feeling of breathlessness. 


We were speaking of this matter the other day, and 
my friend, who teaches physiology, said : 

People used to say that a man was breathless because there was 
more carbon dioxide in his blood than he could expel through his lungs. 
But we know better now. We know that it is n't so much the carbon 
dioxide — although of course that has to be driven off — as it is the 
overtaxed heart that makes us breathless. 

Boys come to me for examination, and I tell them that the heart 
gets tired from overwork, just as the biceps does, and that it is quite 
as possible to strengthen the heart by training as to strengthen the 
biceps. At first I put the boys on easy exercises that tax the heart but 
little ; then day by day I give what is harder until, almost before they 
know it, those boys have developed hearts that are strong enough to do 
hard work without making them breathless. At the same time they have 
trained the heart and lungs to work together in ventilating the blood. 

Speed and Breathlessness. The fact is that we grow 
breathless in proportion to the force which we put into 
any exercise in a given length of time ; that is, the faster 
we do the same thing, the more quickly will breathless- 
ness overtake us. It is easy, therefore, to understand 
an opposite condition, and to believe that the quieter 
we are the less oxygen the tissues will use and the less 
carbon dioxide the body will have to get rid of. 

While we sleep we give off the least carbon dioxide. 
When we sit up the quantity is almost doubled. When 
we run the change is striking, for now, during every 
minute of exercise, the blood carries to the lungs over 
four times as much carbon dioxide as it carried while 
we were asleep. The proportion is not always the same. 


Those who train for athletic sports take the facts about 
oxygen and carbon dioxide into account. They learn to 
manage their running and the work of heart and lungs 
in such a way that neither will be overtaxed until the end 
of the race is near. They are willing to be breathless 
at the very last because they are soon to stop running 
and catch their breath again. But to get breathless at 
the beginning of the race means defeat. And what may 
be said about training the 
machine that, does our 
breathing for us ? Make a 
series of tests for yourself. 

Tests of Chest Capacity. 
Place one hand lightly 
on your chest; place the 

other on your back be- Measured by the doctor 

tween the shoulder blades; inhale slowly until your 
lungs are full, then exhale slowly until they seem empty. 
While you do this, notice that the breastbone rises and 
that the front and rear walls of your chest are forced 
gradually farther apart. 

While you take another long breath and send it out 
again, stand with your hands resting lightly on each side 
of the body just over your lower ribs. Notice that it 
is expansion sidewise this time; you also see that the 
Capacity of your chest has increased greatly. It is as 
if you had pumped air into an elastic bag. 


Increasing the Chest Girth. Take a tape measure and 
get the girth of your chest after you have exhaled all 
you can, and again after you have inhaled all you can. 
Learn from these tests that 
the size of your chest can be 
increased and diminished at 
will, and that its size can 
be increased pennanently by 
frequent exercise of this kind. 
To prove this, measure your 
chest to-day ; then for two 
months take fifteen deep full 
breaths three times a day. 
With each breath expand your lungs as fully as you 
can without really straining them. At the end of the 
two months measure yourself 
again, and you will find that 
your chest measure has in- 
creased. From this you have 
the right to conclude that 
your lungs also are larger. 
Structure of the Lungs. We 

often talk of the lungs as if 

they were a pair of big bags ™"« ^'^ ^""^^^ Expanded 
tucked in under the ribs somewhere, waiting to swell 
out or sink in according as we use them. In a way the" 
notion of the bag Is correct, except that instead of two 


bags, one on each side, we must think of thousands upon 
thousands of microscopic bags, called air sacs. We must 
recall what we learned in Health and Safety, and think 
of these air sacs as the most important part of the 
branching tubes of the lungs. We must remember that 
within the large chamber which the ribs make we have 
two sets of these tubes ending in air sacs. Each set is 
called a lung. The heart lies 
between the right and left 
lungs and is a trifle more on 
the left side than on the right 
Work of the Loi^s. For 
the sake of saving time and 
space a few facts, new and 
old, must be given under 
numbered headings. They 

show how the lungs help us Tubes and air Sacs of the 
throughout our lives. ^""''^ 

1. Blood that enters the lungs is so dark and so 
heavily laden with carbon dioxide — although there 
is also some oxygen in it — that we call it impure. 
Blood that leaves the lungs is so well loaded with 
oxygen that it has gained a bright scarlet color, and 
we call it pure, as indeed it is. Even in pure arte- 
rial blood, however, there is some carbon dioxide. 

2. The lungs are at work not because they them- 
selves need air, but because they serve as a clearing 


house in which oxygen and carbon dioxide may 
change places. Such a central exchange is needed 
because, as we know, each smallest tissue over the 
entire body is in need of oxygen and must be re- 
lieved of its carbon dioxide. It is in the lungs that 
blood unloads itself of most of its useless carbon 
dioxide, loads itself up with oxygen, and streams 
off to some distant destination. Breathing, then, is 
mainly for the benefit of the tissues of the body, 
not for the sake of the lungs themselves. 

3. All the blood of the body comes to the lungs 
and goes away again once every twenty-three sec- 
onds. While it passes through the lungs it does 
not leave the capillaries, but the capillaries them- 
selves are so closely intertwined with the air sacs 
that the two cannot be separated, and since they lie 
so close together, rapid exchanges are taking place 
constantly. Oxygen mixed with the other gases of 
the air is on one side of the animal membrane of the 
air sac ; carbon dioxide, with a little oxygen, is in the 
blood on the other side of the membrane, within 
the capillaries. And as the gases are side by side, 
two of them — the oxygen and the carbon dioxide 
— change places without delay. Oxygen enters the 
blood from the air sac ; carbon dioxide enters the air 
sac from the blood; the red-corpuscle carriers are 
loaded with oxygen in the twinkling of an eye and 


hasten off to unload their cargo where it is needed. 
In the meantime, however, the large supply of car- 
bon dioxide is as unwelcome in the air sac as it 
is everywhere else in the body. It is therefore 
expelled quickly by 
an outgoing breath. 
In this way the body 
relieves itself of car- 
bon dioxide by every 
breath we exhale. 
In view of these three 

important facts it is quite 

evident that large healthy 

lungs will be invaluable 

to any one who wishes 

to take vigorous exercise, 

and that, on the other 

Heart and Lungs in Close 

hand, exercise itself is connection 

the very best thing for -4, left lung; £■, heart; a tube through 

which blood goes to the lungs to be puri- 

lung development. fied; £, windpipe through which air goes 

Inactive Air Sacs. The to the lungs with oxygen for the air sacs 

entire group of sacs should often be compelled to ex- 
pand more fully than they naturally do in the course 
of regular daily breathing, and the best way to expand 
them is not by standing still and taking deep breaths, 
but by using large muscles vigorously, thus compelling 
the lungs to work hard too. 


Many a sagging chest hides from sight multitudes of 
inactive air sacs that have never been expanded through 
hard exercise. Nevertheless, each separate one would 
have worked well and would have increased in size if 
its owner had compelled it to gain capacity and power 
through such hard breathing as comes from fast walk- 
ing, from running, jumping, and swimming, or from lively 
games played out of doors. 

Only by the full breath, which is 
broad as well as deep, does much air 
get into the upper corners of the lungs, 
and these air sacs, left inactive, yield 
quickest to disease microbes. Here it 
Groups of Air IS that tuberculosis most often begins 

Sacs ;^g ■\vork. 

Health and Exercise. Fortunately we get exercise 
whether we use our muscles in work or play, and the 
more we enjoy it the better off we are. Work in garden 
and hayfield, mowing the lawn, and hoeing — all are 
good, provided the body is not overtaxed. If a young, 
frail boy gets too tired, his stomach and other organs 
will not serve him well. Almost every kind of play is 
valuable, unless it overstrains the heart as hard rowing- 
races and basket-ball contests may do. The feeling of 
utter exhaustion, of being exceedingly out of breath, is 
harmful. It must be avoided. The very best exercise 
is that which one gets in moderate walking, running. 



jumping, swimming, riding horseback, and playing out- 
of-door games. By taking the right sort of exercise we 
sleep well, have a good appetite and a clear brain. The 
following rules will help : 

1. Exercise vigorously every 
day. Wecannotexerciseenough 
in one day to last a week, any 
more than we can eat enough 
in one day to last a week. 
Violent exercise should not 
come either just before or just 
after eating. 

2. Make sure to give exer- 
cise not only to arms and legs, 
but especially to the big mus- 
cles of the chest, back, and ^'^ p-^ssaces 

^UJ«™„« C' nasal cavities; A!, mouth 

abdomen. ^^^,^, y. ^^^^^. ^_ ^^. 

The Breathing Apparatus. Instudy- gio'^is; c, glottis, or open- 

. , , . ing from the pharynx into the 

mg our breathing apparatus, recall trachea; u, the end of the 
what you learned about the nose in ^°f'P^'^'^i o.cesophagn. 
Health and Safety^ and bear in mind the following facts. 
Air enters the lungs through tubes that begin with the 
nose and end in air sacs. From first to last these tubes 
are continuous and unbroken, but each part has its own 
name. Here they are; each one is most important — 
pharynx, larynx, trachea, bronchial tubes, bronchioles, 
air sacs. Now take them up for separate study. 


I. Pharynx. Both food and air use this entrance 
to the body through the mouth. Open your mouth 
wide before the mirror. See the soft palate hanging 
downward. This is the curtain which separates the 
mouth itself from the pharynx. Now look just 
beyond and below the palate. See two rounded 
objects, one on each side of the pharynx. These 
are the tonsils. When in good order they hold 
and destroy germs that enter the body with food 
and air. When out of order they grow large and 
inflamed, being diseased by the very germs they 
have captured. When this happens they do the 
body more harm than good, and the doctor must 
cure them or remove them. Nowadays tonsils 
and adenoids are receiving close attention from the 
doctors, because it is known that they are often 
twin hindrances to the breathing apparatus. An 
adenoid is simply a growth of tissue far back in 
the nose. And just because this growth is there, 
it prevents air from going freely to the lungs and 
compels a person to be what is known as a mouth 
breather. Whenever we see a mouth-breathing child 
who is dull and forlorn, unable to learn his lessons, 
and discouraged, we look for adenoids and diseased 
tonsils. Usually both are found, although the follow- 
ing case of a twelve-year-old boy in Cleveland, Ohio, 
speaks of adenoids alone. 


May 1, 1907. Hearing very defective; hears watch at six inches. 
Sleeps badly, snores, appetite poor, frequent colds, restiess, in- 
attentive, stupid, eyesight defective, frequent headaches, adenoids. 

May 3, 1907. Adenoids removed. Eyeglasses secured two 
weeks later. 

June 10, 1907. Hears watch at four feet, breathes freely 
through nose, sleeps soundly, never snores, appetite good, head- 
aches have ceased. Has been transformed into a calm, bright, 
attentive, and well-behaved pupil. 

Thousands of other boys and girls have had the 
same happy experience ; so many, indeed, that now- 
adays it is quite the expected thing for a doctor to 
examine any aiHng child for adenoids and swollen 
tonsils and to remove them if found. It is a simple 
operation and quickly over. 

In the pharynx, with the tonsils, is a device 
which saves us from choking when we eat. This 
is the glottis. It is an opening from the pharynx 
into the windpipe. The cover to this opening is 
called the epiglottis. Whenever we swallow, this 
traplike cover shuts itself down over the glottis 
and prevents food from getting into the windpipe 
where air alone should go. Because the epiglottis 
is down, food slides unhindered through the food 
tube to the stomach. When a person chokes, it is 
because the epiglottis has been slightly raised and 
bits of food have slipped into the windpipe. Joined 
to the pharynx is the next-named part, the larynx. 


2. The larynx^ or voice box. This is a cavity 
inclosed by walls of cartilage,^ and it lies directly 
behind the Adam's apple. Within this cavity are 
stretched bands of tissue called vocal cords. By 
using these cords we produce sounds, have a voice, 
and are enabled to speak and sing. We may also 
train and control the vocal cords and to a large 
extent may have sweet voices or harsh voices as we 
wish. Inflamed vocal cords will produce hoarseness. 
To get pleasant sounds from your vocal cords, place 
the voice in the front of the mouth. You can do it 
as follows : First whisper the sentence, " I will speak 
with my lips and the tip of my tongue." In a whis- 
per we always use the front of the mouth. Now 
vocalize this whisper, that is, give to the whisper, 
sound. You will find that you have kept your voice 
in the front of your mouth. It is easy to injure the 
vocal organs by placing the voice too deep in the 
throat. Many a public speaker does this. While 
the voice is changing, one may yell so furiously at 
a ball game as to strain the vocal cords beyond 
repair. The power to utter sweet sounds is then 
gone forever. Singers are always careful to guard 
their vocal cords from severe strain of any sort and 
from colds which inflame the membranes. Even we 
who are not singers should be careful too. 

^ Something like stiff gristle. 


3. The trachea is the windpipe. It extends from 
the larynx to the lungs, where it divides into two 
branches. These branches are the bronchial tubes. 

4. The bronchial tubes. When we take cold and 
the lining of these tubes becomes inflamed, we have 
bronchitis. Each of the bronchial tubes divides and 
subdivides into ever smaller branches and twigs, un- 
til they end in what are known as the bronchioles. 

5. The bronchioles. These bronchioles themselves 
end in the smallest of pouches, in which are our 
often-mentioned air sacs. 

6. Air sacs are tiny pits on the sides of the 
pouches. Each separate sac is surrounded by the 
finest possible network of capillaries, and the lining 
of the sacs is so thin that it would take twenty- 
five hundred layers of it to make one inch in thick- 
ness. It is within these sacs that the blood in the 
capillaries turns from dark red to bright red, from 
impure venous blood to purified arterial blood. 
The outside covering of the lungs is called the 
pleura. When it is inflamed we have pleurisy. 

Clean Air for the Lungs. From nose to lungs the 
entire lining of the breathing apparatus is a damp 
mucous membrane. It catches and holds microbes and 
bits of dust that may be in the air we breathe. More- 
over, as described in Health and Safety^ thousands upon 
thousands of threadlike cilia are on the lining of the 


nose and of the largest tubes of the lungs. Whether we 
are awake or asleep, they move ceaselessly like velvet 
paddles, always sweeping mucus upward towards the 
mouth, and in this mucus are the captured microbes 
and bits of dust which must be kept from the air sacs 
and thrown out of the body. Thus we see that all the 
breathing we do, and the entire breathing apparatus, is 
for the immediate purpose of supplying the lungs with 
air — clean air if possible. This air holds oxygen for the 
tissues and exchanges it for carbon dioxide from the 
tissues. Without the exchange we should promptly die, 
and the more complete the exchange the better we 
live. For this reason, then, we make the most of our 
breathing apparatus. We stand straight, walk with chest 
expatided, take deep breaths of pure air through the 
nose with the mouth closed, and give strict attention 
to the increase of our lung capacity. It is for each one 
of us to decide whether the air we breathe shall be as 
pure by night as by day, and whether it is always as 
pure as it should be. 

Value of Moist Air. In addition to all else, we should 
take particular pains to supply our homes with fresh air 
that is moist. (Review the directions for ventilation given 
in Health and Safety^ When furnaces, stoves, or steam- 
pipes warm us in winter, indoor air gets so dry that 
the delicate tissues of the nose and lungs suffer. Several 
devices help. For a hot-air furnace keep the water in 


the pan of the furnace always full. Evaporation of this 
water will moisten the air and reach the entire house. 
For steam-heated houses, pans are made to be attached 
to the radiators. These should be kept filled with water. 
It evaporates and moistens the air. Try any device that 
will send moisture into the overdry winter air of our 
homes. As a rule, out-of-door air is moist enough and 
desirable in every way. For this reason, get all of it 
you can. Be out of doors much by day, and sleep on 
a sleeping porch or with windows open at night. 

Getting an All-round Development. With the facts 
about his breathing apparatus before him, let the flat- 
chested person set about his own improvement. Let 
him know that the best-developed leg muscles are of 
little use for running unless heart and lungs are able to 
do their share of the work, for, as some one has said, 
" We run as much with our lungs as with our legs." 
We next study foods, the source of all our energy. 


1. If you were ever thoroughly out of breath, describe the sensa- 
tions you had. 2. In a hard run, what happens to the tissues of the 
body? 3. What gas is produced by tissues as they work? 4. What 
gas do they greatly need? 5. Through what stream do the tissues 
get rid of their carbon dioxide and receive their oxygen ? 6. Why does 
the blood stream need to flow fast? 7. What three things combine 
to bring about breathlessness ? 8. WTiat can be done to strengthen 
the heart ? 9. When does carbon dioxide form fastest ? 10. When do 
we use the most oxygen? 11. When does a man give off the least 


carbon dioxide and call for the least oxygen ? 12. Why is the heart over- 
taxed when we run hard? 13. What does a trained athlete learn about 
managing the work of the heart and the lungs? 14. During exercise, 
which muscles give a hurry call for oxygen? 15. Which two organs 
of the body need to be trained in their relation to each other? 

16. Mention tests which show that lung size can be increased 
17. How many lungs have we? 18. Where are they? 19. What is 
an air sac? 20. When is blood called impure? 21. When is blood 
pure? 22. What is the condition of the blood when it enters the 
lungs? when it leaves the lungs? 23. In what way are the lungs a 
storehouse? 24. What exchange goes on in the air sacs? 26. Where 
do the red corpuscles carry the oxygen? 26. Do we breathe for the 
benefit of the lungs or of the tissues? 27. How long does it take 
blood to make the circuit of the body ? 28. Describe the way in which 
oxygen and carbon dioxide change places in the lungs. 29. Why are 
large lungs an advantage to the body? 30. How may their size be 
increased? 31. What are the best kinds of exercise for the lungs? 
32. What danger comes from inactive air sacs ? 33. Where does tuber- 
culosis most often begin ? 34. Why should breathing be done through 
the nose and not through the mouth? 35. Why should air be well 
cleaned before it enters the air sacs ? 

36. Mention the names of different parts of our breathing apparatus. 
37. What can be seen in the pharynx? 38. Of what use are the 
tonsils ? 39. When diseased what should be done to them ? 40. What 
are adenoids? 41. How do they hinder breathing? 42. Describe the 
condition of the Cleveland schoolboy before and after his adenoids were 
removed. 43. Describe the glottis and the epiglottis. 44. Where is the 
larynx? 45. What cords are in it? 46. What can be done in training 
the vocal cords? 47. Give another name for the windpipe. 48. What 
happens when the bronchial tubes are inflamed ? 49. What is the spe- 
cial work of the air sacs ? 50. What kind of substance lines the entire 
breathing apparatus ? 51. Of what use is it ? 52. Where and what are 
the cilia? 53. What is pleurisy ? 



Experiments in Eating. In 1903 Professor Chittenden 
of Yale University conducted some scientific experi- 
ments on a rather large scale. He began with himself, 
enlisted the help of others, and finally had in hand 

Soldiers who served on the Eating Experiment 

thirteen soldiers whose ages ranged from twenty-two 
years and six months to forty-three years. 

Close attention was given to the men in several ways. 
At quarter of seven each morning they were weighed. 
This was necessary, for they were eating about half as 
much meat as usual, with somewhat less of other kinds 
of food, and it was important to know each day whether 
they were gaining or losing by the new diet. 


At seven came breakfast Here each separate kind of 
food was weighed before it was given to the man who 
was to eat it. What he did not eat was also weighed, 
that Dr. Chittenden might know just how much had 
been used. Moreover, these men were allowed to eat 

only such food as was served to them. All eating 
between meals was strictly forbidden. 

Aside from this close care about their food, the men 
were not hampered in many ways. They went to the 
theater sometimes, worked in the Yale gymnasium an 
hour a day, had regular drill under their officers, and 
went to bed at ten o'clock. 

When they left New Haven six months later, Dr. An- 
derson, director of the gymnasium, wrote as follows: 


The men were not above the average standard physically when they 
began their work, this standard being set by applicants for positions as 
firemen and policemen, not by college students. At the end of the 
training they were much above the same standard, while the strength 
tests were far greater than the averages made by college men. 

These tests did not settle all food questions, but they 
seemed to make it clear that even soldiers may gain 
strength on much less meat than they have been in 
the habit of eating. As for the rest of us, science has 
proved that the welfare of the body is closely related to 
the food we give it, that the kind of food makes a dif- 
ference in the quality of the work, that he who works 
little harms himself when he eats much, and that 
growing children need much more food than their 
inactive elders. 

What Food does for the Body. All scientists agree that 
food does two things for the body : 

1. Food builds tissue; that is, it makes the body 
grow by adding fresh tissue for the building of 

. muscle, bone, blood, brain, etc., and it makes the 
body new by replacing all tissues as fast as they 
wear out. 

2. Food produces energy by which the body does 
the work of muscle, bone, brain, and beating heart, 
while at the same time it keeps itself warm. Food 
so used is the fuel for our engines. No engine 
runs well when fuel is lacking. 


We eat, then, for the purpose of meeting one or the 
other of these two great demands of the body, and our 
success or failure in Hfe may easily turn on what we 
know or do not know about the value of our food. 

The Five Food Substances. When Professor Chittenden 
planned meals for his soldiers, his main thought was not 
as to whether he should give them beefsteak, mutton 
chops, fish, eggs, bread, or vegetables, but whether or 
not he was giving them the right proportions of certain 
substances which living bodies need if they are to do 
good work. These substances are known as proteids, 
carbohydrates, fats, water, and mineral matter. They are 
the general materials out of which our bodies are built, 
and they are so closely united with each other in blood 
and tissue that only the chemist can separate them. 
The next page gives a table made up from reports pre- 
pared by the United States Department of Agriculture. 
It shows how materials which the body must have are 
distributed in some of the foods we eat. In this table 
the single word " carbohydrate " is used instead of the 
two words " sugar " and " starch." ^ 

^ Notice that some of the substances in the table are moist, while others are 
dry ; and remember that before many of the dry foods are eaten, a g^eat deal of 
water is added to them. This is notably true of the cereals, of rice, and of flour. 
For example, what we buy as one pound of rice at the grocer's comes to the table 
as nearly four pounds of moist food. The chief difference between dry and moist 
foods is simply that when we eat dry foods we take less of the food and more 
water. Vegetables, fruit, meat, milk, eggs, puddings, and pies are moist foods. 
See the quantity of water in them which the table shows. 











Bread . . . 
Wheat flour . 
Oatmeal . . 
x\ice . • • • 
Green peas . 
Potatoes . . 
Milk .... 
Cheese . . . 
Roast beef . 
Leg of mutton 
Veal .... 
Chicken . . 
Canned salmon 
Egg .... 
Butter . . . 
Fresh oysters 
Macaroni . . 
Oyster crackers 
Gingerbread . 
Sponge cake . 
Apple pie . . 
Squash pie 
Tapioca pudding 
Fresh asparagus 
Dried beans . 
Fresh cabbage 
Green com • 
Dried peas . 
Fresh tomatoes 
Bananas . . 
Fresh cranberries 
Dried prunes . 
Almonds . . 
Peanuts . . 
Brazil nuts . 
Soft-shell walnuts 

' I ' I ' I ' I ' I 
10 20 30 40 50 


I ■ I 
70 80 



* These tables are made up from facts supplied by Bulletin 28 (revised edition) 
of the United States Department of Agriculture. 


Studying the Cost of Foods. Study the food chart and 
decide which articles cost most. Into the expensive 
group will go all the meats. Dried vegetables and maca- 
roni will be in the other group. Notice the amount of 
proteid and of carbohydrate in the different foods. For 
example, compare dried beans and roast beef. Take 
macaroni, add cheese to it, and we have an admirable, 
inexpensive food. It contains all the proteid we need, 
with abundance of carbohydrate and fat. In dried beans 
and dried peas we also have all the proteid we need, and 
carbohydrate too. So far as the food supply of the body 
is concerned, these inexpensive foods do just as much 
for us as expensive meats. Besides, they have the ad- 
vantage of being free from damaging microbes — which 
is more than can be said of meats. Indeed, meat harbors 
so many microbes that decay easily sets in both before 
and after it is eaten. 

Perhaps we wonder why Professor Chittenden took 
such care about his food substances, and why we our- 
selves should give so much time to the study of the 
same subject. The facts answer these questions. 

Plants as Food Producers. Our entire food supply comes 
from living and growing things, that is, from plants and 
animals. Plants gather food for themselves from earth, 
air, and water. Each .plant is therefore a producer, a 
food factory, while at the same time it is a storehouse of 
energy. Each takes carbon dioxide from the air, water 


from the earth, sunlight from the skies, and by its mar- 
velous power it combines these things that are not foods 
into the foodstuff starch. We find starch in fruits, vege- 
tables, and grains. It is more abundant on the earth 
than any other food, and we speak of it as if it were a 
simple substance. Instead, the entire starch supply of 
the world is composed of unnumbered small granules, — 
easily seen under the microscope, — and each separate 
granule is wrapped within its own tiny cellulose enve- 
lope. To a large extent all plants are made up of starch 
and cellulose. When starch substances are cooked, the 
cellulose envelope breaks up. This lets the starch out, 
and it becomes digestible food. It is, indeed, for the sake 
of breaking up the envelope that we cook our vegetables 
and our grains so carefully. Starch is a carbohydrate, 
so also is sugar, which is very much like starch in its 
chemical make-up. We find starch in green fruit. This 
turns to sugar as the fruit ripens, and the fruit is then 
sweet. Some vegetables also contain sugar as well as 

Carbohydrate for Energy. The carbohydrates starch 
and sugar are the substances which — with fat — give 
the body most of its energy. They do no building of 
bone, brain, or muscle, but act as fuel for the furnace of 
the body, giving power to muscles, bones, heart, brain, 
and every other organ. If we eat more carbohydrate 
than we need at the time, the body stores part of it up 


as fat and sends the rest of it from the lungs as carbon 
dioxide, or from the skin and kidneys as water. No part 
of this waste is left in the blood. Carbohydrate stored 
up as fat is often as useful 
to the body in time of need 
as money in the bank is to 
a man who lacks cash and 
needs to make a purchase. 
The Proteids. An animal 
is not a genuine food pro- 
ducer; that is, it does not 
manufacture food from water, 
earth, sunlight, and air as 
plants do. It is primarily a 
consumer of food. So true 
is this that if animals were 
compelled to use each other 
as food, leaving plant foods 
untouched, the animal life of 
the world would soon vanish 

Animal proteid is found 
abundantly in all animal foods 
— in milk, cheese, lean meat, 
chickens, fish, and eggs. Plant 

stored up as fat. The diagram proteid IS for the mOSt part 
shows that the body keeps a good deal r i ■ i -i 

of this on hand ready for use found m peas, bcans, lentils, 

This SHOWS what Proportion of 
THE Human Body is composed of 
Each Suhstance which we take 

Little carbohydrate appears, because 
most of the sugar and starch which we 
eat is used up in the shapie of heat and 
muscular work and sent from the body 
as carbon dioxide. When we eat more 
carbohydrate than we need, thi 


and nuts. Grains also contain proteid, and there is a little 
of it in most vegetables. Study the table for interesting 
items about the proportions found in different foods. 

Proteid for Tissue Building. Proteid — whether from 
plant or from animal — is the substance which the body 
uses for building up its tissues. When a child is grow- 
ing, proteid supplies him with material for longer bones, 
larger muscles, bigger brain, etc. When a muscle is 
worn down through exercise, proteid is used to build 
it up again.i 

If we eat more proteid than we need, the left-over 
part will not be stored up by the body as is the case 
with left-over carbohydrate. Instead, it has to be worked 
ovgr by the liver and sent out of the body through the 
kidneys. By constantly eating too much proteid, some 
people give the liver and kidneys more work than they 
can do. This is made plain in Chapter XL We there 
learn that proteid waste in the blood stream is even more 
harmful to the body than clinkers are to the furnace. 

The Fats. Animal fat comes in the shape of butter, 
lard, and suet. Vegetable fat comes as oil from nuts, 
from fruit like the olive, and from cotton seed. 

The Minerals. The body gets part of its needed min- 
eral matter from table salt, celery, lettuce, and spinach, 
all of which are valuable to us. When too much salt is 
used it is harmful. 

1 Since there is nitrogen in proteid, it is sometimes called nitrogenous food. 


Need of Drinking Water. Drink at mealtime if you 
wish, but Ttever wash down a mouthful of half chewed 
food. Avoid ice-cold water, because it chills the stomach 
and delays digestion. If digestion is delayed, fermenta- 
tion is apt to set in, and this means indigestion. Drink 
six glasses (that is, three pints) of water every twenty- 
four hours. The body needs this for several reasons. 

1. It flushes the system, dilutes harmful sub- 
stances, and helps keep the liver and the kidneys 
in good condition. 

2. Over half the substance of our bodies is noth- 
ing but water, and every day the body sends off 
about three pints of it through the sweat glands 
and the kidneys. If this amount is not replaced, 
we are not so well off. 

Rules for Right Eating. In view of all these facts, eat- 
ing begins to look like a pretty solemn matter, and we 
ask ourselves if we must be always thinking about 
carbohydrates, proteids, and fats and of the quantity of 
each which we are eating. Certainly not. The one sen- 
sible way is to remember what the food substances are 
and to eat meat but once a day. Even for growing 
children this is quite often enough ; for ailing old folks, 
whose bodies do little tissue building, it is often too 
much. Be on the safe side, therefore, and be sparing 
of meat. Eat vegetables and fruit liberally, however. 
But in doing this bear in mind the laws of proper 


eating ^ — tharoughness of mastication^ regularity of meal- 
time^ no eating between nteals^ save of such fruit as 
oranges, and no ^^stuffing^^ even at mealtime. Eat until 
fully satisfied of such nourishing foods as have been pre- 
pared, then stop. To be hungry means that the cells of 
the body are calling for food-fuel. To feel this hunger 
is a good sign, and it should be satisfied. 

Many people abuse their digestive apparatus until at 
last it rebels. For the help of such sufferers careful 
charts have been prepared. These show how much food 
of different kinds should be used each day. Thus, by 
carefully weighing and measuring the amounts of pro- 
teid, carbohydrate, and fat that they eat, afflicted people 
are sometimes able to get relief. Better far not to reach 
the point where such care is needed. The truth is that 
the entire digestive apparatus does its best work when 
there is no anxiety about the food that is being eaten. 
The best plan, therefore, is to remember the great 
general laws about proteids, carbohydrates, and fats, 
to eat some of each every day, to obey all the laws of 
careful eating, and to give no further worrying thought 
to the matter. 

Balanced Menus. When Professor Chittenden selected 
beans, cheese, or eggs for his men, he gave them little, 
if any, meat. As best she can, every housekeeper 
should do for her family what Professor Chittenden did 

1 As given in Health and Safety, 


for his soldiers. She should supply well-balanced meals. 
This means that she should make wise combinations 
of foods containing proteid, carbohydrate, and fat. She 
should not serve at the same meal too many kinds 
of food that contain the same substance. Compare the 
two columns of menus given. Decide why the left- 
hand ones are desirable, the right-hand ones undesirable. 
Study the food table and make up menus of your own. 
Put into each one some proteid, some fat and mineral 
matter, and much carbohydrate. Those who study food 
facts believe we should eat fully five times as much 
carbohydrate as proteid. 

Food for Bulk. In this connection it should be stated 
that food is needed not for nourishment alone but fpi 
bulk as well. Were it not for this, we might be content 
to have our food condensed into small pellets and 
swallowed quickly with a mouthful of water. But the 
stomach and the long food tube need to exercise them- 
selves on food that has bulk to it. Vegetables and fruit 
are especially useful for this purpose because of their bits 
of cellulose tissue, which make bulk and pass along 
through the body without being digested. Graham 
flour and grain with the hull on are valuable for the 
same reason. 

Vegetarians. Multitudes of people know that they can 
get all the proteid they need in other foods than meat. 
When they eat no meat they are called vegetarians. The 




Breakfast i 

Baked apples 

Cereal and cream 

Toasted whole-wheat 

Breakfcut 2 

Oranges, prunes, or 
other fruit 

Boiled hominy 

Graham gems 

The Reason Why 

Breakfast. This meal should be light and 
easily digested. The hardest work of the day 
comes in the forenoon, and it is a mistake to 
work hard after a hearty meal. In the heaith- 
yi^ breakfasts few articles are provided. In 
the unheaUhfulhxtsHisia&Xs there is too much. 
Then, too, fried things always digest slowly. 
Coffee is objectionable. If you wish some- 
thing hot, use a cereal drink. 


Breakfast i 

Cereal, cream and sugar 

Fried eggs and bacon 

Waffles and sirup 


Breakfast 2 

Sausage, fried potatoes 


Hot rolls Coffee 

Luncheon i 

Scalloped com 

Cottage-cheese salad 

Graham bread 

Pineapple sauce 


Luncheon 2 

Macaroni and cheese 

Baked tomatoes 

Lettuce, French 

Fig tapioca, whipped 

Luncheon. In the healthful luncheons we 
have cheese instead of meat for the proteid. 
Com and macaroni supply carbohydrate. 
Lettuce leaves give bulk ; so also does the 
coarse part of graham bread. In the ithheaUh- 
^/luncheons there is too little carbohydrate. 
As a result, too much proteid will be eaten. 
Pickles are indigestible. It takes four hours 
to digest ham. Doughnuts are objectionable 
because they are fried in deep fat. That which 
digests slowly is apt to ferment in the 
stomach and produce gas. Tea contains 
tannin and the poison theine. 

Luncheon i 

Fish chowder 

Cold meat 

String beans 

Baked apples 


Luncheon 2 

Minced ham on toast 

Doughnuts Coffee 

Dinner i 

Tomato soup 
Fish or 

Leg of lamb 
Baked potatoes 
Creamed carrots 

Fruit gelatin 

Dinner 2 

Vegetable soup 

Roast chicken 

Browned potatoes 


Cranberry jelly 

Fmit salad 

Prune whip 

Dinner. Look at the unhealthful dinners. 
Notice that they have proteid in oysters, 
in soup, roast, vegetables, salad, mince pie, 
and cheese. Coffee and pickles are bad. 
There is far too much proteid and far too 
little carbohydrate in these unhealthful din- 
ner menus. The healthful dinners have 
soup with no proteid ; potatoes baked, which 
is the best way ; almost no proteid in the vege- 
tables ; no proteid in the salad, very little of it 
in the desserts. These dinners are well bal- 
anced. When there are several courses to a 
meal, and especially when meat is provided, 
make sure to have light soups, salads and des- 
serts, and serve vegetables that are not rich 
in proteids. Raw oysters should not be eaten 
unless we know where they come from. They 
often live in water spoiled by sewage and by 
typhoid microbes. Many people have taken 
typhoid from contaminated oysters. 

Dinner i 

Bean soup 

Leg of lamb 

Mashed potatoes 


Spiced pickles 

Suet pudding 


Dinner 2 

Raw oysters 

Split-pea soup 

Roast beef 

Mashed potatoes 

Lima beans 

Fmit-and-nut salad 

Mince pie Cheese 



millions of people in India, China, and Japan live mostly 

on rice, with its seventy-nine per cent of carbohydrate. 

The Teeth. Whatever we eat, teeth 
do the chewing and must be kept 
in order. These bits of bone in 
the mouth are covered with enamel 
— hard, white, brittle, and easily 
cracked. Breaking nuts, opening a 
knife, or seizing nails and other hard 
substances with the teeth may crack 
the enamel, and once damaged it 
will never mend itself. Instead, mi- 
crobes will find their way through 

it. After this they will work their way to the central 

pulp of the tooth, with its small 

blood vessels and nerves. And 

when microbes reach tooth nerves 

we have the toothache — jumping 

toothache, generally. Microbes are 

in fact the worst enemies teeth 

have. They live and multiply on 

bits of food between the teeth and 

on the gums. As they work their 

way through the enamel, we say the these teeth were 

tooth is decaying, as indeed it is. traightened 

To get rid of microbes and prevent decay, keep the 

teeth clean ; wash them with water, soap, and toothbrush. 


after breakfast and every night before going to bed. 
Once a day pull soft silk floss between the separate 
teeth. This will draw out food fragments which the 
brush does not reach. Use tooth powder or paste two 
or three times a week. This is often enough. Besides 
keeping the teeth clean, go to a dentist twice a year. 
He will keep them in good repair. Nor is this all. 
Remember what Health and Safety says about " squirrel 

One Half of the Permanent Set of Teeth 

mouth " — how it happens and how to prevent it. To 
do proper chewing, the upper and the lower teeth 
should be opposite each other. A dentist can compel 
crooked teeth to grow straight, and the matter should 
be attended to while the jaw is still young. Even five- 
year-old children may help themselves by doing some 
downright, energetic food-chewing every day. If cereal 
is used, serve dry toast with it. Use soft cereals less, use 
crispy toast more. The chewing required for the toast 


will give exercise to jaws and gums, will draw blood to 
the chewing apparatus, and will thus give health and 
vigor to the teeth themselves. Such chewing will do 
more than anything else to save children both from 
"squirrel mouth" and from adenoids. 

Since we know that our whole supply of food gets 
into use through what the body does to it after it 
has been broken up by the teeth and swallowed, we 
are now ready to understand Dr. W. B. Cannon's experi- 
ments with cats under the X ray, described in the next 


1. Give an account of Professor Chittenden's food experiments with 
soldiers. 2. Did these men eat more or less than other men ? 3. What 
was the result? 4. What did the tests prove about man's need of meat ? 
5. What persons should eat least meat? 6. Mention two things that 
food does for the body. 7. What are the five food substances? 
8. Whence do plants get their nourishment ? 9. Whence do animals get 
theirs? 10. What do the carbohydrates include? 11. Study the food 
table and tell which foods are richest in proteids ; in carbohydrates ; in 
fats. 12. What is said about dry and moist foods? 13. What substance 
surrounds each separate starch granule and must be broken up by cook- 
ing ? 14. Which food substance gives us energy ? 16. If we eat more 
carbohydrate than we need, what does the body do with the surplus ? 

16. What is animal proteid ? plant proteid ? 17. What does the body 
make of proteid food ? 18. If we eat more proteid than we need, what 
becomes of the surplus ? 19. Where does the fat in our food come from ? 

20. What are the general laws of proper eating? 21. Why do we 
feel hungry? 22. When Professor Chittenden selected beans, cheese, 
or eggs for his men, why did he give them little meat? 23. Why are 


creamed potatoes more nourishing than plain boiled potatoes ? 24. Why 
is macaroni and cheese so nourishing ? 25. How much water should we 
drink ? Why ? 26. What do we mean by a "balanced menu" ? 27. Give 
the menu for a healthful breakfast ; luncheon ; dinner. 28. Why is bulk 
of food needed ? 29. What gives bulk ? 30. Describe the teeth and tell 
why they should be kept clean. 31. How is this done ? 32. What is the 
cause of toothache ? 33. Why should crooked teeth be straightened ? 




Food Experiments with Cats. These experiments were 
carried on in the laboratory of the Harvard Medical 
School, and the record of the work was published in 
1898. Cats were chosen because they are easy to get 
hold of, ready to eat when they are fed, ready to sleep 
at almost any time, and easily controlled. Even among 
cats, however, Dr. Cannon had to choose carefully, for 
only those who were good-natured were useful. 

Having made his choice, he took bread, mixed into it 
a harmless chemical called bismuth,^ fed it to his cats, 
and waited for results. The bismuth was put in for only 
one reason: its presence in the food made it possible 
to get a shadow of the image of the stomach by means 
of X rays. From the shadows he hoped to discover ex- 
actly how the stomach moves during the time that it is 
digesting its contents. Dr. Cannon was fortunate in the 
cats he chose, fortunate in his helpers, and fortunate in 
what he was able to learn through the X rays; for he 
learned facts which had never been proved before. 

^ The exact chemical name is bismuth subnitrate. 



Under the X Ray, After being fed, at a quarter of 
eleven in the morning, the cat was put in place for its 
shadow picture. At eleven o'clock work was well under 
way in the stomach, and once every half hour after that, 
until twelve minutes after six in the afternoon, the kindly 
cat consented to have its shadow studied. Dr. Cannon 
traced the shadows one by one, so that an exact record 
was kept of the size of the stomach from the time of the 
hearty feeding until there was nothing left to be digested. 

During this time there was an interesting course of 
events. When first seen the stomach looked like a small 
leg of ham with a curled-up tail to it, but when six 
o'clock came the leg shape had disappeared entirely, 
leaving nothing but the tail to show where the food had 
been. Moreover, by this time the cat seemed hungry 
and called for food, with which it was promptly rewarded. 

The Stomach during Digestion. The diminishing size 
of the stomach was perhaps one of the least important 
lessons learned that day; for while the cat slept, and 
while the X rays were focused on its stomach, another 
fact was noted. It appeared that food which had newly 
arrived stayed quietly in the upper end of the stomach 
as if it were in a reservoir. Here the saliva which had 
been swallowed with the food had a longer time to 
do its share in the work of digestion. But as fast as 
supplies were needed farther on, this reservoir contracted 
itself and sent its contents forward, a little at a time. 




Contraction of 

Cat's Stomach 

(much reduced) 

DURING Digestion 

It was also seen that the firm walls 
of the lower part of the stomach began 
to contract in a series of wavelike 
movements. These waves started near 
the middle of the stomach and moved 
towards the smaller end of the elastic 
bag. Every ten seconds a new wave 
took its start from about the same spot 
and traveled the same course down to 
the pylorus at the smaller end. 

Indeed, whenever the shadows were 
studied during the day, these waves 
were seen to be following each other 
with unceasing regularity. Moreover, 
as time passed and as digestion pro- 
gressed, this middle part of the stomach 
grew gradually more and more slender, 
like a neck, while the larger end stayed 
large for a longer time. 

Through his study of shadows Dr. 
Cannon learned that within about fif- 
teen minutes after food is swallowed a 
slender jet of softened food goes with a 
spurt through an opening at the lower 
end of the stomach and out into the 
tube which is the beginning of the 
small intestine. 


Entrance and Exit of Food. For all animals, including 
man, the entrance of the stomach is controlled by what 
is known as the circular cardiac muscle. This stays 
closed except when food must enter. The exit for the 
contents of the stomach is guarded by another strong 
circular muscle, called the pylorus, or keeper of the gate. 
And well does this gatekeeper do its work. Sometimes 
with every wave that rolls in its direction it opens 
wide enough to allow a spurt of digested liquid food, 
called chyme, to go through, but sometimes it stays 
persistently shut while wave after wave pushes in vain 
in its direction. 

Use of Bismuth. To get an explanation of this uneven 
action of the pylorus. Dr. Cannon induced the cat to 
swallow a small, specially prepared tablet, made up of 
starch paste and bismuth. He then watched the prog- 
ress of this pellet in the stomach. He saw it stay for 
a long time in the cardiac end; saw it gradually make 
its way farther and farther down as it was sent forward 
by the waves of contractions; and finally saw that for 
forty-two minutes after the pellet reached the pylorus 
that watchful gatekeeper allowed nothing to pass 

Over and over again the pellet and the mass of soft 
food in which it floated came up to the pylorus as if 
to demand free passage through, and over and over 
again the soft as well as the hard was positively rejected 


and sent shooting backwards, only to come again and 
again to be rejected. 

This was kept up until finally the most fluid of the 
food was held back no longer. It went onward. Later 

The Human Stomach 
Food reaches the stomach from the mouth through the < 
digestion goes on, bile runs from the liver directly into the 
times the opening of the bile duct is shut, and instead of entering the ir 
bile passes into the gall bladder, where it is stared until needed. The outline of 
the pancreas is shown by a dotted line 

the pylorus seemed to give up all protest. It seemed to 
conclude that there was no hope of ever softening that 
bismuth and so allowed it to go on in company with 
food which was properly prepared. The pylorus is in- 
deed a faithful guardian of the food supply. 


Undigested Substances. From this experiment it is 
evident that any hard substance in the stomach is not 
only slow in passing on through the pylorus, itself, but 
that it delays the progress of even such food as has 
already been reduced to chyme — food which should be 
receiving its next course of treatment in the food tube. 
The main objection to slow digestion is that after food 
has stayed too long in the stomach it ferments and gives 
off gases which stretch the walls of the stomach and 
cause distress of various kinds. 

The next time you eat in a hurry and are tempted 
to swallow unchewed lumps of food, think of the bis- 
muth pellet and control yourself in time. 

Emotions that Hinder Digestion. During the X-ray 
experiments there came an unexpected turn to affairs 
one day. Thus far Dr. Cannon had been fortunate 
enough to have dealings with amiable cats only. They 
had eaten when he wished, had been quiet and welt 
mannered during the experiments, and had slept when 
required. In addition, their stomachs had gone steadily 
to work when food was put into them and had kept 
ploddingly at it until digestion was completed. 

But a different type of cat came to Dr. Cannon's 
hands one morning. This one ate as promptly as the 
others, and when the X ray was arranged, the shadow 
showed at first that the usual regular wave action of 
the muscular walls was taking place. Suddenly, however, 


the animal lost his temper. He seemed to feel out- 
raged at what was being done. He refused to pun- 
as did the other cats; he insisted on being released. 
Being in such a state of mind, he was useless and had 
to go. But before he was dismissed, the X ray showed 
that all the waves had stopped; so much so, that the 
stomach was as inactive as if it were empty. 

This led to close observation of the connection be- 
tween the feelings of a cat and. the behavior of its 
stomach during digestion. Then camq the surprising 
discovery that whenever a cat is unhappy, or disturbed 
in its mind by anger, anxiety, or distress of any descrip- 
tion, the muscular action of the stomach comes to an end. 

To prove this conclusively those who carried on the 
experiments had to tease a well-disposed cat a little, 
even while it was under the rays. Before the teasing 
it purred gently, and the wave contractions swept on 
with rhythmic regularity. But when the teasing began 
and when the cat felt mental distress every wave ceased ; 
the stomach stopped its work abruptly and absolutely. 
But if at this point Dr. Cannon stroked the cat, it 
was at once happy and purred. And with the purring 
began again the squeezing and the regular progress of 
the waves along the walls of the stomach. 

Happiness and Good Digestion. Doctors have always 
known that an unhappy man does not digest his food 
so well as the same man when happy, but none have 


known just why this is so. 'It is evident, however, that 
there is some close connection between happiness and 
the power of the stomach to keep up the squeezing 
movement of its waves. 

In view of this discovery 
we plainly see that if we 
wish good work from our 
own stomachs we must be 
neither worried nor anxious 
nor angry, either during the 
time that we are eating or 
as long afterwards as food 
is in our stomachs waiting 
to be digested. For the sim- 
ple sake of health, therefore, 
the calm and happy mind 
is greatly to be desired. 

When to take Exercise. For 
health's sake never take hard 
exercise of body or mind just 
before or just after a meal. 
Such exercise draws blood 
away from the region of the 

stomach just when special the road the food takes 
supplies of it are needed for digestion. We should have 
a restful as well as a happy feeling at mealtime, and only 
by planning for this condition shall we get it. 


The Digestive Apparatus. The following definite state- 
ments are needed for the closing of this section: 

1. The alimentary canal is the one food avenue 
of the body. It extends from the mouth downward 
through the center of the body and is of different 
size and shape in different parts according to the 
work it has to do. Throughout its course its walls 
are controlled by muscles which differ with the kind 
of squeezing and pulling which is required of them. 
In addition, the entire alimentary canal is lined 
with mucous membrane, delicate, pink, and elastic. 
It is always moist, so that food may move through 
it easily. 

2. The mouth is a cavity supplied with teeth for 
the breaking up of food into bits, a tongue for roll- 
ing food from side to side, and saliva for the soften- 
ing of this food. When ready to be swallowed, the 
pulplike mass of chewed moist food is laid hold of 
by muscles at the back of the mouth and forced 
through the pharynx into the oesophagus. 

3. The (esophagus extends onward to the stomach. 
Through it food goes down, not as a stone into 
a well, but as a package which careful muscles 
pass along by a squeezing movement. On its way it 
slides safely over the epiglottis, which has closed down 
suddenly over the glottis. When the food has passed, 
the epiglottis lifts and the glottis is open again. 



4. The stomach is that part of the alimentary 
canal which has been stretched out into a good- 
sized pouch. Its entrance is guarded by the strong, 
circular cardiac muscle; its 

exit by the pylorus muscle, 
equally strong and equally 
circular. While food is in it, 
the stomach keeps up a con- 
stant kneading movement, 
which sweeps like slow waves 
from the cardiac to the py- 
loric end. At the same time 
gastric glands in the walls 
of the stomach pour out 
gastric juice from thousands 
upon thousands of tiny open- 
ings, thus softening still fur- 
ther the food that came from 
the mouth. When all is as 

liquid as pea soup the py- y,j^j^, ^^^^ ^^^^ ^^^ 
loric muscle relaxes, and the velvet uningofthe 
prepared stream of chyme 
shoots its way through into 
the small intestine. After it 
enters the intestine the food substance is called chyle. 

5. The small intestine is about twenty feet long, 
yet it is only a single part of the alimentary canal 

A cut through the waU of the 

tube, showing some dark blood 

vessels and four villi 


The entire tube is coiled up in compact fashion just 
below the stomach and the liver, and it expands 
or contracts with the amount of chyle that it holds. 

6. The villi. The mucous-membrane lining of the 
intestine is covered with slender projections called 
villi, of which much will be said a little later on. 
They absorb the soluble food for the use of the body. 
As food passes through the small intestine it grows 
constantly softer because several fluids are being 
added to it. 

7. The large intestine and the colon form the final 
five feet of the alimentary canal. Here the food con- 
tinues to be absorbed somewhat and to be passed 
along until all that is left is sent from the body 
as waste. 

Peristaltic Action^ and the Villi. Keeping these facts 
about the canal itself in mind, we are prepared to under- 
stand how it is that the food supply in the tube gets 
into the blood supply of the body. In other words, we 
are ready to appreciate the wonderful importance of 
peristaltic action and the villi. 

In the same laboratory of the Harvard Medical 
School, and probably on the identical cats already de- 
scribed, a second set of experiments was made, in order 

^ This means *' the peculiar wormlike, wave motion of the intestines, produced 
by the contraction of the muscular fibers of their walls, forcing their contents 



to determine what is the history of chyme after it has 
gone through the pylorus into the tube of the intestine 
and has its new name '* chyle." 

The entire scientific world was in doubt as to precisely 
what happens in the tube until, through Dr. Cannon's 

/ \ / \ 

\ / \ / 

The Food Tube and its Contents 

A., the tube as it contracts at regular intervals ; B^ the contents of the tube after 
the first contraction ; C, after the second contraction ; Z>, after the third contrac- 
tion. The line through the middle of the oval piece shows where each was divided 
by the tube as it tightened just there. The arrows show how the new halves 
were alternately forced apart and driven together by the repeated contraction 

of the tube itself 

continued experiments, the mystery was explained by 
the discovery of a series of surprising facts. 

Activity in the Food Tube. At first the X rays showed 
the shadow of the chyle as it lay along in the various 


loops of the folded tube. All was inactive and quiet for 
a season. Then came slight warnings — a quiver at first, 
a mere agitation. Then without further delay, activity 
began in earnest. The stretched-out length of chyle 
within an entire loop was suddenly divided into sepa- 
rate bits of equal size. The tube, indeed, without ap- 
parent cause, had tightened itself at regular intervals; 
like a flash it had divided its contents into a series 
of oval masses of equal size. After this it halted for 
a moment. But within two seconds there was another 
contraction, and each bit was now divided through the 
middle; their halves were compelled to unite with 
neighbor halves on either side, and a series of new 
whole ones appeared. 

Thus, back and forth, every two seconds, the rapid 
peristaltic action was continued. 

The small masses of chyle were alternately so quickly 
divided and so quickly forced together again that Dr. 
Cannon speaks of them as rushing together '*with the 
rapidity of flying shuttles, the little particles flitting to- 
wards each other and the larger segments shifting to 
and fro, commonly for more than half an hour without 

In the meantime the food within the tube was advanced 
but slowly on its way. It seemed to stay in place for no 
other purpose than to be acted upon by the squeezing 
and relaxing of the tube. Whether the chyle was thin 



or thick, whether the contraction was slow or swift, the 
squeezing was kept up so unweariedly that each particle 
of chyle was affected by it. All that lay within the folds 
and turns of the small intes- 
tine was brought into contact 
with the sides of the tube 
thousands of times while it 
was gradually being absorbed. 
That which could not be used 
went on into the large intes- 
tine, whence it would finally 
leave the body. 

Relation of Chyle to the 
Villi. To an ignorant person 
this endless activity might 
seem to be a waste of energy 
and a needless hindrance to 
the chyle as it is worked along. 

In point of fact, however, rapid ■^< ^ c^ll which manufactures mu- 

r , , , , cus; S, the outside layer, which 

movement of chyle through absorbs chyk; C, capillaries to 

the food tube would be a dis- ^"pp'^ =^=!; ,^'""^ ™'"^ ^^°°^- 

Z>, lymphatic 

tinct disadvantage; for from 

the time food is swallowed until its journey is ended, the 
one necessity is that it should be thoroughly prepared 
to be used by the regiments of threadlike villi which 
line the small intestine. Chyle, indeed, is improved by 
every juice that is mixed with it and by every squeeze 


which it receives before it is absorbed by the villi. So 
true is this, that food which does not get the treatment 
it needs will be rejected by each villus which it meets 
as it travels downward and will end by forming part of 
the final waste of the body. 

Food Waste. With all that we eat there is, of course, 
much that can never be turned into chyle and blood. 
We know, however, that this is useful as bulk. But 
nothing hinders digestion much more, or breaks down 
general health much faster, than the results which come 
from retaining waste in the body after it should be sent 
off. Waste decays in the body just as meat and vege- 
tables decay in the pantry on a warm day. Both in the 
pantry and in the food tube, decay comes from the action 
of microbes, and from both places decaying food should 
be cleared away promptly. The habit of getting rid of 
waste at a definite hour each day, whether in the morn- 
ing or in the afternoon, is of priceless value, for that 
which the villi reject is worse than useless to the body. 
More is said of this later. 


1. Describe Dr. Cannon's experiments with cats. 2. Where does 
the wavelike motion of the stomach begin? 3. Describe the changing 
shape of the stomach during digestion. 4. How soon after eating does 
food begin to leave the stomach? 5. Name the muscle that guards the 
outlet. 6. How does the pylorus act when an undigested substance 
reaches it? 7. What did Dr. Cannon's experiment prove? 8. Why is 


it a disadvantage to have food detained too long in the stomach? 

9. What emotions have the power to stop all action of the stomach? 

10. What condition of mind helps at the dining table? 

11. Describe the alimentary canal; the mouth; the oesophagus; the 
stomach. 12. Where is the cardiac muscle? the pylorus muscle? 
13. Describe the kneading movement of the stomach. 14. What is 
manufactured by gastric glands ? 15. How soft does food get in the 
stomach? 16. What is it then called? 17. Describe the way chyme 
leaves the stomach. 18. What is the length of the small intestine? 
19. Where is it located? 20. What is chyle? 21. What and where 
are the villi? 

22. What was the object of the second set of experiments on cats ? 

23. Describe the action of the small intestine as shown by the X ray. 

24. How did chyle move through the tube? 25. Is a rapid or slow 
movement of chyle desirable? 26. What is the work of the villi? 
27. Why is chyle squeezed up against them? 28. What becomes of 
food that is not absorbed by the villi ? 29. From the time food is 
cooked and eaten until its journey is ended, what is all the preparation 
for ? 30. What is each villus like ? 31. What is the great object of peri- 
staltic action? 32. What happens if food is not thoroughly prepared 
for the villi ? 33. Where does food meet its final test ? 34. What hap- 
pens to food if it is kept too long either in the pantry or in the 
food tube? 



The Chemical Fluids of Digestion. No chemist in any 
laboratory is able to manufacture chemicals quite so 
marvelous as those the body manufactures to digest 
our foods. These fluids do two things to the food we 
swallow : 

1. They soften it thoroughly and dilute it. 

2. They so change it that even substances which 
will not dissolve in water — beans, potato, bread, 
and most other foods — are so thoroughly dissolved 
by digestive fluids that the villi can absorb them. 

This chemical process of dissolving food and getting 

it ready for the villi is called digestion. There are five 

digestive fluids. Each is manufactured in the body and 

sent into the alimentary canal, and each does its own 

special kind of chemical work. Follow them in order, 

from the mouth downward. 

I. Saliva^ from glands in the mouth. This not 

only softens food but changes starch into sugar. 

Try the following experiment: Take a tablespoon- 

ful of cornstarch paste. Add a teaspoonful of saliva, 

mixing it thoroughly with the paste. Keep it at 



blood heat for a few minutes. It will not only grow 
thin and watery, but it will soon have a sweetish 
taste. The saliva has turned the starch into a 
kind of sugar. This is easily used by the villi. 

2. Gastric juice^ from gastric glands in the walls 
of the stomach. In this 
juice there are three 
important chemicals — 
pepsin, rennin, and hy- 
drochloric acid. Rennin 
turns milk into curd 
as soon as it reaches the 
stomach. This is most 
important, for otherwise 
the milk would go on 
through the pylorus 
without waiting to be di- 
gested. After it is turned 
to curd by the rennin, 
the pepsin of the gas- 
tric juice is able to take hold of it and digest it. 
Curd is a proteid, and pepsin digests proteids if 
hydrochloric acid is present. Gastric juice is the 
most important proteid digester of the body. 

3. The remaining three digestive fluids are all 
found within the small intestine. Bile^ which comes 
from the liver through the gall duct, digests fat^ 

A Salivary Gland 

Ay artery ; F, vein ; iV, nerve ; T', the 

tongue; Z>, the tube through which 

saliva, manufactured by the gland, 

is emptied into the mouth 


which was simply melted in the stomach. Pancreatic 
fluids which comes from the pancreas, is a marvel of 
power. It digests all three substances — carbohy- 
drate, proteid, and fat. Intestinal juice^ coming from 
the inside lining of the whole length of the tube, 
helps do the general digesting. It gives final touches 
to all food sent down for the use of the villi. 
Number and Structme of the Villi. It would seem, then, 
that from first to last each mouthful of food which we 
swallow is being put into shape for the villi, and that 
they use it or not without the slightest reference to our 
wishes in the matter. This indeed is true, and the 
number of these independent workers is counted by the 
hundred thousand and the million. Each separate one is 
a tiny finger-shaped structure, ready to absorb such chyle 
as shall meet its demand; each stands beside its neigh- 
bor, helping to make the soft velvety lining of the twenty 
feet of tubing; each does its independent work, yet all 
are united in drawing nourishment from the chyle and 
in sending it on to the body through the blood. 

Just here certain facts should be reviewed and con- 
densed : 

I. It is through the lining of the small intestine 
that practically all substances must pass — whether 
proteid or carbohydrate, fat or mineral matter — 
which are to enter the blood from the food we 


2. The villi are, in point of fact, the lining itself, 
drawn up into slender tubes for the sake of increas- 
ing the surface against which the chyle must be 
pressed. They are sometimes called the roots of the 
body, for they suck up nourishment 

from chyle just as tree roots draw 
liquid from the earth. 

3. Food passes through the villi 
much as lymph and plasma pass 
back and forth through the sides of 
the tubes that carry blood. This 
food must therefore be liquid, for 
the villi cannot absorb any solid 

4. The great object of peristal- 
tic action is to wash the chyle up 
against the villi, so that they may 
be constantly bathed with fresh 
supplies of it. 

5. The mouth with its teeth and 
its saliva softens food and prepares 
it for swallowing ; the stomach with 
its gastric juice softens it still further and prepares 
it for the pylorus; the food tube, with its contri- 
butions from the liver and the pancreas, and the 
juices from its own lining, gives to what we eat its 
final preparation for the villi. 

\ Gas- 

Branches 01 

TRic Gland Highly 

Gastric juice is here 


6. When the chyle which is squeezed against the 
villi is such as they can use, they absorb it and 
send it on through other tubes into the current of 
the blood. When, however, this chyle is not liquid 
enough, or not changed enough in other ways, 
they refuse it as firmly as if they knew it would 
be harmful. 
Mistakes in Eating. For each of us almost any well- 
cooked food can be turned into chyle which will pass 
through the villi; yet many a thin man, and many a half- 
nourished woman, shows by every sign of face and figure 
that the villi are not getting what they can accept 

In almost every such case the explanation lies in some 
mistake which the person is making. Perhaps he eats so 
fast and chews so little that the saliva does not have a 
chance to do its share of work. Perhaps he is so busy 
just before and just after eating, that blood is drawn 
away from the stomach, leaving it less vigorous than it 
should be. Perhaps he worries so much, is so anxious 
and troubled about many things, that gastric juice fails 
to form, and thus its part of the work is not done. Or 
it may be that the unfortunate person has overeaten 
until his whole digestive system has rebelled. Whatever 
the cause, we know that we are nourished or starved ac- 
cording as we have been successful or not in preparing 
the chyle for its last examination. If teeth and tongue, 
saliva, stomach, gastric juice, bile, and pancreatic juice 


have done their work well, the final test will be success- 
fully met — the villi will accept the food, and we shall be 
nourished. If the test is not met, we shall suffer from 
lack of nourishment. 

At this point there arises an important question. 
Does anything we do ever help or hinder the flow 
of our digestive juices? 

Appetite and Gland Activity. In studying this subject 
Professor Pavlov, a Russian investigator, fastened a small 
tube so ingeniously to the mouth of a dog that the 
saliva ran into it as fast as it was formed. He then 
made tests and described them, one after the other. 

I now offer this, dog a piece of flesh and, as you see, the tube fills up 
at once with saliva. I stop tempting the dog, hang on a new test tube, 
and give it a few pieces of flesh to eat ; once more a strong secretion 
of saliva results. A new tube is now attached to the funnel, the dog's 
mouth is opened, and a pinch of fine sand is thrown in ; again there is 
a flow of saliva. One may employ a number of substances in this way, 
when a similar effect is always produced. 

Flow of Saliva. Many different students have estab- 
lished the fact that the mouths of dogs, and of men too, 
are supplied with three sets of salivary glands, and that 
for dogs and men alike one or the other of the two 
following causes is enough to make saliva flow: 

1. A great desire for some special kind of food. 

2. The chewing of the food. 

Prove these statements for yourself. Think of the 
most delicious thing you know anything about, and 


notice the effect on your mouth. Then again, when 
mealtime comes, take a dry crust and see what you 
can do with it by the mere act of chewing. Use your 
jaws vigorously, and before long you will find that you 
have turned that dry bread into something as easy to 
swallow as a mouthful of mush. 

Saliva and Carbohydrate. A wise man with a weak 
digestion often chooses toast, crackers, and crusts rather 
than the most delicate custards. He makes this choice 
because he knows that dry food requires more chewing 
than soft food, and that for this reason it will receive 
more from his salivary glands. He realizes that the 
more saliva we mix with the carbohydrate which we eat 
in bread, potatoes, and other foods, the better prepared 
will that carbohydrate be for its next course of treat- 
ment. He knows that even after food is swallowed, the 
saliva will continue to act upon it in the stomach for 
a season. 

We chew food thoroughly for two reasons: first, to 
soften it ; second, to mix it with saliva, which will change 
some of it and prepare it for its next course of treatment. 

Milk Digestion. Carbohydrate does not stand alone in 
its need of help from the mouth. A baby is allowed to 
draw no more than the finest stream of milk through 
the mouthpiece of his bottle, because when milk reaches 
the stomach it is curdled at once, and it is much better 
to have it curdle in small flakes, that can be more easily 


digested, than in one large lump which will be slow in 
digesting. Young babies who are allowed to drink milk 
rapidly are not likely to gain so much nourishment 
from it as they would if it reached the stomach a 
little at a time. The same is so true for older people 
too that we should all take our milk in sips and not in 
a pouring stream which will curdle in a mass as soon 
as it reaches the stomach. Here the colorless acid fluid, 
gastric juice, renders priceless service by digesting it. 

Proteid Digestion. A dog swallows an unchewed piece 
of raw meat, and his stomach digests it — not by tearing 
it to pieces, but in a real way by dissolving it through 
the aid of gastric juice, his gastric juice being much 
stronger than ours. Even the human stomach digests 
unchewed raw meat, but cooked meat needs more chew- 
ing. Still it is gastric juice that digests both cooked 
and uncooked meats. The small gastric glands which 
manufacture this liquid are packed snugly side by side 
within the lining of the stomach. Each is supplied with 
its separate tube, ending in its own special outlet. And 
the fluid which these hosts of glands secrete and empty 
into the stomach flows faster or slower according to 
circumstances. Dr. Pavlov discovered this through his 
dogs. He found that he could often control the flow 
by his experiments. Here is one which he describes: 

The stomach has been washed out half an hour ago, and since then 
not a drop of gastric juice has escaped. We begin to get ready a meal 


of flesh and sausage before the animal, as if we meant to feed it We 
take the pieces of flesh from one place, chop them up, and lay them in 
another, passing them in front of the dc^'s nose. The animal, as you 
see, manifests the Lveliest interest in our proceedings, stretches and 
distends itself, endeavors to get out of its cage and come to the food, 
chatters its teeth together, swallows saliva, and so on. Precisely five 
minutes after we begin to tease the animal in this way, the first drops 
of gastric juice appear. The secretion grows 
stronger and stronger till it flows in a 
conaderahle stream. The meaning of this 
experiment is so clear as to require no ex- 
planation ; the passionate longing for food, 
and this alone, has called forth a most 
intense activity of the gastric glands. 

In carrying on these experi- 
ments Professor Pavlov made it 

A Fragment OP THE Lining , . ,, , , i_ u . ■ i 

OF THE Stomach Magnified plain that dogS should not Simply 

TwENTv DiAMETEBs jjg tcmptcd But sHould be fed 
Each spot shows the mouth of ■^y^ whatever tempted them. 

a gastnc gland through which r 

gastric juice flows into the Effect of Appetite OB DigestioE. 
"^^"^ Several other facts were brought 

out by the same tests. Each was valuable from a scien- 
tific point of view, and I give them in close succession: 

1. The more eagerly a dog desires food the more 
gastric juice will flow. 

2. Gastric juice flows fastest and longest in 
connection with food that is enjoyed the most; 
for some dogs this is raw meat, for others cooked 
meat. Dogs have preferences as well as men. 


3. The mere fact that something is in the dog's 
stomach does not make the juice flow. 

4. The more the juice flows the better will the 
food digest. 

From these important facts, learned through the study 
of digestion in dogs, men now know why it is that a 
good appetite helps digestion. Indeed, the call of the 
body for food — if it is not too long continued — is one 
of the greatest blessings of life, and he who eats only 
when he has earned an appetite for food is sure to 
gain the most nourishment from that which he puts 
into his stomach, because while it is there it will receive 
the richest supply of gastric juice. 

But aside from digestion itself, there is the great 
matter of preparing food for the glands even before 
we eat it. 

Why we Cook our Food. Turn back to the food table 
and decide why we do so much cooking. There are 
three reasons: 

I. For the sake of health ; to make the food more 
digestible. Cooking is really a first step in the 
process of digestion, and there is far more danger 
that food will be undercooked than overcooked. 
Take oatmeal and other breakfast foods for exam- 
ple. They contain a good deal of starchy carbo- 
hydrates (study the table again), and those who do 
not understand about cellulose may consider them 


ready to be eaten long before the tiny cellulose cell 
has been broken up by boiling. An hour of boil- 
ing for oatmeal, and half an hour for more finely 
powdered grains, is none too long. Undigested food 
ferments easily and produces gas. This is harmful 
to health. 

2. To destroy microbes which may be in the food 
or on it Recall the facts about this given in 
Health and Safety. Re- 
member that cooking kills 
microbes, and that a dead 
microbe is as harmless as 
a dead lion. 

3. To improve the taste 
of food. Glance along the 
list of foods and think of 
^ ^XlTiZZT"' ">e difference it makes in 
the taste of these vegeta- 
bles, grains, and meats, whether they are cooked or 
not Also remember the fact that digestive juices 
flow fastest when we enjoy our food. Cooking helps 
us to enjoy it 
Harmful Substances. It is perfectly possible, however, 
to enjoy what does harm. For years people believed that 
chocolate and cocoa were good drinks for children, and 
that tea and coffee were bad for them. Nowadays, how- 
ever, food experts condemn all these drinks. They say 


that the same poison is in each drink, and that it stimu- 
lates brain, heart, and nervous system. In coffee this 
stimulant is called caffeine; in cocoa and chocolate, theo- 
bromine ; in tea, theine. There is more of the harmful 
substance in tea and coffee than in cocoa, so that cocoa 
and chocolate are less harmful than tea and coffee, but 
in every case the stimulant is as bad for tired heart, 
brain, and nerves as a whip is for a tired horse. Then, 
too, in tea and coffee there is 
a substance called tannin. The 
more the drink is boiled the 
more tannin it holds. " Puckery " 
tea contains much tannin and is 
most objectionable. Tannin is 
used for the tanning of hides. 
When we swallow it in tea and ^ 

From the faEKo of the Bean 
coffee we put into the stomach The larger granules are starch, 
a substance that can disturb the the smaller ones are prowid 

best working of the digestive apparatus. If tea and 
coffee are made by simply pouring boiling water over 
them, they contain little tannin, but the caffeine and 
theine remain. 

Candy and sweetmeats in quantity do harm too, be- 
cause our digestive apparatus has no device for easily 
getting rid of large amounts of cane sugar. None of it 
is digested in the small intestine. If, however, a person 
is healthy, and if candy is eaten moderately at mealtime, 


it will do no real harm. But if it is eaten between meals, 
when the stomach is empty, it becomes an irritating acid 
in the stomach. The following is quoted: 

A German scientist observed in experiments upon a dog that a solu- 
tion containing six per cent of cane sugar caused irritation, with red- 
dening of the mucous membrane. A ten-per-cent solution produced a 
dark-red color, with great irritation, and caused the animal great pain. 

From the work of the stomach and of the large num- 
ber of small digestive glands, turn now to the daily and 
hourly occupation of the largest glands of the body, our 
vigilant and untiring protectors, the liver and the kidneys. 


1. How many digestive juices are there? 2. What two things do 
digestive juices do for food ? 3. Give the names of the chemicals which 
are in gastric juice. 4. What does rennin do to milk in the stomach? 

6. Why is this action important? 6. What does pepsin do to curd? 

7. Is curd a proteid or a carbohydrate ? 8. What is the most important 
proteid digester of the body ? 9. What three digestive juices are found 
in the small intestine? 10. Where does bile come from? 11. What 
does it digest ? 12. Where does pancreatic fluid come from ? 13. What 
three things does it digest ? 14. What does intestinal juice do ? 15. How 
do the villi help the food to pass through the lining of the small intestine ? 
16. Why is the lining itself drawn up into these slender tubes called 
villi? 17. How numerous are they? 18. Why are the villi called the 
roots of the body ? 19. Why does food need to be a thin liquid ? 
20. What is the great object of peristaltic action? 21. Describe the 
history of a mouthful of food, from the time we begin to chew it until 
the villi absorb it. 22. When a person is half nourished, what may be 
the trouble ? 


23. Tell what you can about the effect of tempting a dog with meat. 
24. How many sets of salivary glands are there ? 25. What two things 
make saliva flow ? 26. Why does a sensible man with a weak stomach 
eat dry toast rather than delicate custard? 27. How does saliva affect 
starch ? 28. After food is swallowed, where does saliva continue its work > 
29. Give two reasons why we should chew food thoroughly. 30. Why 
should babies, and older persons also, take their milk in sips and not 
in a pouring stream? 31. What can gastric juice do to raw meat?^ 
32. Which needs more chewing, raw or cooked meat ? 33. Describe the 
gastric glands. 34. Describe the tests with dogs which proved certain 
points about the flow of gastric juice. 35. What should always be 
done after tempting a dog with food ? 36. Under what circumstances 
does gastric juice flow fastest and longest? 37. What can you say 
about the advantages of hunger and a good appetite? 38. Give the 
first reason why we cook our food. 39. How long should we boil 
oatmeal and other cereals ? 40. Give three reasons why we cook our 
food. 41. Why is it an advantage to enjoy the taste of our food? 
42. Why are tea, coffee, cocoa, and chocolate objectionable ? 43. Why* 
is much candy harmful? 



The Liver — what it Is and what it Does. If you are 

thin enough to do it, you might sHp your fingers up 
under the edge of your lowest ribs on the right side. 
There you will feel the outline of the largest gland in 
your body. The liver weighs between three and four 
pounds, and it is to this organ that the villi send much 
of that which they draw up from the chyle.^ The follow- 
ing are the occupations of the liver: 

1. It changes part of the liquid food which it 
receives from the villi into a sugar substance called 
glycogen. It stores up this glycogen in its own liver 
tissues and keeps it there until it is needed for the 
work of the body. The liver is thus a glycogen 
storehouse, a bank of deposit. 

2. It takes certain wastes from the blood, makes 
them over, and forwards them to the kidneys in 
the blood stream, to be sent from the body by 
the kidneys. 

1 Part of the food supply which the villi gather from the small intestine — 
especially the part that holds digested fats — does not go direct to the liver. 
Instead, it travels upward first and reaches the heart by the way of the neck. 



3. It manufactures bile as needed. This is sent 
through the gall bladder and the bile duct into the 
small intestine. There it helps digestion and after- 
wards escapes with the other wastes of the ali- 
mentary canal. Into the bile go certain captured 

As THE Normal Liver looks 
<After Horaley) 

poisons. For example, if peas or pickles colored 
with copper are eaten, the liver seizes the metal, 
sends as much as possible into the bile, and stores 
up the rest within its own cells. It does this to keep 
the poison from getting into the blood stream and 
going to the rest of the body. It is only when there 


is too much poison for the liver to manage that it 
escapes into the general blood stream and becomes 
a menace to different organs of the body. So also 
with other poisons. In a very real way the liver is 
our daily protector from death by poisoning. 
Clearly enough, no man who knows the facts and who 
wishes to make sure of his health will care to ignore the 
welfare of his liver or to act as if he were ignorant of 
the laws which control it. Nevertheless, many of the dis- 
coveries about these laws are so recent that even some 
well-informed people have failed to hear about them. 

This is true of my neighbor who complained about his 
liver the other day. He said the doctor advised him to 
eat less, to exercise more, and to give up his beer until 
he was in good shape again. But against this he pro- 
tested. He said, " Can't I judge what is good for me by 
my own feelings?" The doctor said he could not, and 
the doctor was right. Follow the argument closely. 

Effects of Alcohol on the Liver. Those of us who have 
ever seen a piece of raw liver know how extraordinarily 
bloody it is. We also know that every piece of liver is 
always deluged with its own blood. This is inevitable, 
because the liver is provided with an enormous number of 
small blood vessels, each one of which is in active service. 
When, therefore, the doctor gave my neighbor that 
advice about beer, he was advising according to his knowl- 
edge of the effect of alcohol on blood vessels in general 


He knew that wherever there is an unusual supply of 
capillaries and blood-carrying tubes of all sizes, there will 
alcohol do its paralyzing work. He knew that when 
blood vessels in the liver are somewhat paralyzed and 

A Drunkard's Liver ruined by Alcohol 
(After Horale;) 

enlarged beyond their usual size, the liver itself is sure 
to suffer in a serious way. 

When a doctor examines liver after liver as he finds 
them in the hospital and in the dissecting room, he 
counts the ignorance of the unfortunate men no laughing 


matter. " A drunkard's liver again," he will say as he 
opens up the telltale gland. " No wonder the man died. 
It's a wonder he lived as long as he did, with a liver 
of this sort to purify his blood supply for him. It has 
swollen to twice its natural size. 
The tubes are distended and in- 
active ; the cells are loaded with 
fat." Any such inactivity pre- 
pares a man to fall an easier 
prey to microbe diseases and to 
die earlier than he might have 
died. Life-insurance societies 
know this so well that some of 
them charge even the moder- 
ate drinker more for the same 
amount of insurance than they 
charge the non-drinker. 

The Kidneys — what they Are 
and what they Do. Two other 
glands cooperate with the liver 
as protectors of the body. These 
are the kidneys. They He on 
each side of the lower part of the back, and their struc- 
ture is a marvelous arrangement of closely packed micro- 
scopic tubes which are netted about by vast numbers of 
capillaries. They weigh from four to six ounces apiece. 
Their special work is to remove poisons and wastes that 

The Kidneys i 

Waste Water 
A, artery; B, vein; C, tube 
through which water leaves the 


accumulate in the blood. All this waste is then sent, as 
a liquid, through two slender tubes into the bladder. 
Thence, by another tube, it leaves the body. 

In view of what they do, the kidneys may well be 
called the life preservers of the body. For after stomach, 
intestines, villi, and liver have done 
what they can for us, the left-over 
wastes and poisons are finally 
thrown upon the kidneys for dis- 
posal. If, then, the kidneys fail us, 
the outlook for the body is serious 
indeed. Brain, muscles, glands, 
arteries, and veins will now suffer 
because, one and all, they draw 
their supplies from an impure 
blood stream. 

Effects of Alcohol on the Kidneys. 

■' A Cut through thk 

When, therefore, the jovial drinker kidney 

pours his beer and his whiskey Notice the clusters of slender 
■ , t ■ , I I , 1 • tubes: each separate one 

mto his stomach, let him remem- ^i^^t be called a iiio^^^y 
ber that the alcohol of that drink 
will pass quickly into his blood, that within a few min- 
utes it will find its way to the cells and the tissues of 
his life-preserving kidneys, and that, in course of time, 
those tender tissues will become inflamed and less able 
to do even so much as their usual work. Nevertheless, 
while in this condition, there will pour upon them not only 


the alcoholic blood itself to be grappled with but all the 
unconquered wastes and poisons which the overworked 
liver could not eliminate. The struggle will keep on for 
a season. Unpurified blood will grow more and more 
impure, until both the liver and the kidneys are over- 
come at last. When this happens the doctor may say: 
"You are suffering from auto-intoxication. Your whole 
system seems to be out of order, but the main trouble 
is with your liver and your kidneys. They seem to be 
literally worn out." 

Auto-intoxication. When a doctor speaks of auto- 
intoxication — and most of them do it nowadays — he 
means that the body is being injured by poisons made 
within itself. As it happens, a great part of these poi- 
sons comes from certain microbes which multiply within 
the intestine. Some of them are really harmless. Others 
are known as the putrefactive microbes. They live 
mostly on the proteid foods in the intestines, and as 
they multiply they produce poisons which in some cases 
are most detrimental to the body. Nevertheless, these 
poisons — toxins, they are called — are sucked up by 
the villi along with the useful food and are sent to the 
liver to be poured into the general blood supply. Imag- 
ine, then, the work which is forced upon the liver as it 
tries to take the toxins from the blood stream. What 
the liver cannot attend to, the kidneys must remove. 
If both these organs have been damaged by alcohol, or 


by any other cause, they cannot do full work. The blood 
is then not cleared of poisons as it should be, and the 
result is auto-intoxication. This shows itself in headache, 
irritability, or discomfort of one sort or another. Serious 
illness may follow, just because a weakened body is at a 
disadvantage when disease microbes attack it : 

How to prevent Auto-intoxication. There are three 
ways to prevent auto-intoxication: 

1. Be mindful of the liver and the kidneys and 
do not put into the body any food or drink which 
may weaken the power of either. Even when these 
organs are in their best condition, they have about 
all they can do to save us from auto-intoxication. 
Do not lessen their power to serve you. 

2. Avoid much animal proteid. This decays faster 
than vegetable proteid in the alimentary canal, 
and the faster the decay the more the putrefactive 
microbes multiply. Think how much sooner meat 
spoils than beans. Guard yourself against alcohol, 
against tea and coffee, and against all highly sea- 
soned foods. Also eat sparingly of the following 
articles: pies, soggy dumplings, rich cake, dough- 
nuts, and everything soaked in frying-fat. All are 
more or less indigestible. If you ever eat them, 
therefore, do thorough chewing before the swallow- 
ing. Turn them into thin paste in your mouth. 
When taken in this condition they do less harm. 


3. Get rid of waste from the large intestine every 
day. Food waste should pass through the entire 
length of the alimentary canal within from sixteen 
to twenty hours after it is swallowed. If waste is 
not fully cleared away, it acts like a poison to the 
body. We then say the person is constipated. In 
this condition the body is threatened, for microbes 
in the intestine are multiplying in constantly swarm- 
ing hosts, and auto-intoxication is almost sure to 
result. As a rule take no medicine for constipation. 
Instead, take regular exercises that make the mus- 
cles of the abdomen work hard, and eat graham or 
bran bread — or even a tablespoonful of bran itself 
— with every meal. One may buy this from any 
grocer. Bran helps by giving bulk for the intestine 
to act upon. Eat freely of lettuce, celery, vegeta- 
bles, and fruit. Be sure to drink the needed three 
pints of water every day. 

4. Avoid tainted food. So-called ptomaine poison- 
ing often follows the eating of tainted meats. And 
thousands of babies die because their milk food 
is spoiled by microbes. This is why we insist on 
having fresh meat and clean milk. 

Headache and Auto-intoxication. It should be stated 
clearly that headache is more often due to auto- 
intoxication than to any other one cause. (Headache 
from eyestrain is spoken of later.) To get rid of the 


pain, clear the body of its waste. Also, for immediate 
relief, wrap a hot, wet towel about the face and the 
back of the neck. This expands the capillaries and 
draws blood from the brain. Never take drugs unless 
everything else fails and the doctor orders it. The drug 
habit is easily formed, and it is a fearful master. 

Other Glands. The same damaged blood which ham- 
pers the liver and the kidneys, giving us headache and 
other ills, is also a disadvantage to every other gland of 
the body. Each is a mass of soft tissue made up of 
separate working cells. In size our glands vary all the 
way from the four-pound liver to the smallest sweat 
gland in the skin. The product of any gland is called 
its secretion. Some glands send their secretion through 
a duct to its destination. For example, the surface of 
the body receives sweat secretion from the sweat glands. 
The eyeball receives a secretion from the lachrymal 
glands. Five other sets of glands — about which we 
have already studied — send their secretions into the 
alimentary canal. Still other glands are called ductless. 
These ductless glands send their secretion directly into 
the blood as it passes through them. They have no need 
of any duct. Nevertheless, what they manufacture is of 
vital importance to the body. Among ductless glands 
are the two thyroids in the neck. When these are dis- 
eased, people often suffer from what is known as goiter. 
But whether glands have ducts or not, a damaged blood 


supply is a disadvantage to them all. This is part of 
the reason why tight clothing is so objectionable. 

ni Effects of Snog Gannents. The fashion for small 

waists comes and goes, but harm comes and stays 

even when the pres- 

J I sure of the lacing 

^^^^^t^"^ ^^'v,^ is not very great. 

/^ N. Imagine some new 

/ \ kind of X ray that 

/ \ could show what lac- 

\ ing does to different 

parts of the body. 

Here are the items 

of damage: 

I. The liver 
is forced into 
such small com- 
pass that its cap- 
illaries and tiny 
tubes are hard- 
pressed upon. 
IHSIDB Groans before the i^cng ^hus crowded 

they cannot do 
good work in preparing needed glycogen for the 
body. Neither can they fully purify venous blood 
of its waste. As a result, unpurified blood goes on 
its way, carrying danger to all parts of the body. 


2. The stomach is so crumpled up and crowded 
that indigestion follows, than which nothing is more 
fatal to a beautiful complexion. 

3. The long folds of the small intestine are 
pushed downward, and are so pressed upon that the 
entire tube becomes 

inactive. Food moves 
slowly through it, 
and as this food de- 
cays, gas is formed 
and toxins multiply. 
This gas stretches 
the walls of stomach 
and intestine alike, 
and pain follows. 

4. After lacing has 
gone on for some 
time the muscles 
which make up the 
walls of the abdo- 

(After Tracy) 

men become relaxed 

and flabby through lack of exercise. As a result, 
the organs which these muscles should hold in place 
are left sagging downward. After this each organ 
has to carry on its business as best it can under 
most unfavorable conditions. If illness follows, the 
suffering person should blame no one but herself. 


5. Lacing so cramps the lower lung cells that mul- 
titudes of air sacs are wholly out of service and 
breathing has to be done through the lifting of the 
chest — not through the better way of spreading out 
the ribs. How loose then should our clothing be? 
Importance of Loose Clotliii^. Stand with your back 
to the wall, with head, heels, and elbows touching it. 
Now draw a deep breath. 
Can you do this without 
feeling that bands, strings, 
buttons, or hooks are be- 
ing pulled rather vigor- 
ously ? Our clothing 
should always be loose 
enough to allow us to 
breathe freely. Bands 
should never bind the 
waist, and the weight of 
heavy clothing should be 

carried by straps that 
The Shape the Ribs should have 1 e j.t. 1. u 

hang trom the shoulders. 

Remember that the more easily the gland laboratories 

are allowed to do their work, the better able are we 

to endure the wear and tear of life and to resist disease 

of every sort. 

The Two Body Cavities. In a way it may be hard to 

think of the trunk of the body as a double-story set of 

The Diaphragm when ii 
The organs from above it and below it have been removed 


apartments, but such it is. For, stretching across us from 
side to side, a little above the waistline, is a strong, broad, 
elastic partition of rnuscle, called the diaphragm. Below 
it, in one cavity, lie liver, stomach, intestine, and other 

Exercises to strengthen the Muscles of the Abdominal Wall 

(After Schmidt) 

important organs; above it, in another cavity, are the 
heart and lungs, with the large and small tubes which 
belong to them. Through the diaphragm go a large 
artery, a large vein, and the tube which carries food 
from the mouth to the stomach. 


Above the diaphragm, then, we find the organs of 
respiration and circulation; below it lie the organs of 
digestion and the great gland, the liver. Above the 
diaphragm, blood is ridding itself of carbon dioxide; 
below the diaphragm, blood is getting supplies of 
nourishment to carry to the tissues of the entire body. 

The Rhythmic Movement of the Diaphragm. But what 
active share does the diaphragm take in all this ? Draw 
a deep breath. As you do this, you are not only 
raising your ribs but also contracting your diaphragm 
from every side, taking the arched shape out of it, 
and forcing it down upon the organs below. Each 
breath gives those lower organs good exercise, for the 
diaphragm is the largest and the strongest breathing- 
muscle we have. When it contracts, air rushes down 
into the lungs. When it relaxes into its normal arched 
shape the pressure is lifted, air rushes out of the lungs, 
and the upper cavity is smaller again. 

Liver, stomach, and intestines all gain vigor from 
the rhythmic movement. 

Aid to the Organs of Excretion. The rhythmic move- 
'ment is important because our organs of excretion need 
the exercise that it gives them. These organs are the 
lungs, which get rid of carbon dioxide; the small and 
large intestines, which rid us of food waste ; and the kid- 
neys, which rid us of waste water and its poisons. The 
skin is the fourth great organ of excretion. It helps the 


kidneys through its discharge of perspiration and will 
be discussed later. 

Notice the difference between excretion and secre- 
tion. Excretion is waste from the body. Secretion is 
something manufactured by an organ of the body. 


1. Name the largest gland in the body. 2. Give its position; its 
weight 3. Mention its three kinds of work. 4. Through what duct 
does bile go to the small intestine? 5. What kind of waste goes into 
the bile? 6. Why does the liver store up certain substances in its 
own cells? 7. When it cannot store it all, what becomes of the rest? 

8. What does a doctor advise men to do when they have liver trouble ? 

9. Why is a piece of raw liver bloody ? 10. Why is alcohol especially 
harmful to the liver? 11. What often happens to the liver through 
the use of alcohol? 12. What do life-insurance societies do about 
charging drinkers for their insurance ? . 

13. What other glands are greatly affected by alcohol? 14. Give 
the location of the kidneys ; their appearance ; their weight. 16. What 
is their special work? 16. Where do they send their waste? 17. If 
they fail . in their work, what parts of the body will suffer ? Why ? 

18. Mention facts which those who use alcohol should remember. 

19. Besides alcohol, what other substances will reach the kidneys in 
the blood stream? 20. When liver and kidneys are overcome, what, 
will the doctor probably say? 

21. What is meant by auto-intoxication? 22. What are putrefactive 
microbes ? 23. Where do they multiply ? 24. What do the villi do with 
the toxin which the putrefactive microbes manufacture ? 25. What does 
the liver do with these toxins when they reach it ? 26. If the liver can- 
not take them all out of the blood, what must the kidneys do ? 27. If 
both the liver and the kidneys have been damaged by alcohol, or by any 


other cause, what happens to the blood ? 28. Mention three ways by 
means of which one can prevent auto-intoxication. 29. Why is it neces- 
sary to keep the body well cleared of its waste substances ? 30. How 
much water should we drink each day? 31. Which decays faster in 
the alimentary canal, animal proteid or vegetable proteid? 32. Why 
should we reduce our supply of animal proteid? 

33. What are the manufacturing organs of the body ? 34. What is 
the structure of each gland ? 35. How do they vary in size ? 36. What 
is the product of a gland called? 37. Mention different ways in which 
glands send off their secretion. 38. What secretion, from what glands, 
is poured out on the surface of the body? 39. What glands supply 
the eyeball with moisture ? 40. How many sets of glands send their 
secretions into the alimentary canal? 41. What are ductless glands.^ 
42. How does their secretion get into the blood ? 43. When thyroid 
glands are diseased, what is the name of the disease? 

44. What happens to the liver when a person laces? 45. What is 
the effect of lacing on the stomach? on digestion? 46. How does 
lacing hinder the work of the small intestine? 47. Why do the walls 
of the abdomen become relaxed and flabby ? 48. Is this an advantage 
or a disadvantage to the work of the internal organs ? 49. What does 
lacing do to the lower lung cells? 50. What is the diaphragm? 
51. What organs are above the diaphragm? below it? 52. When 
relaxed, what shape does it take and what happens to the air in the 
lungs? 53. Name the organs of excretion. 54. Define excretion; 
secretion. 55. How loose should clothes be about the waist ? 56. If 
gland laboratories and the diaphragm are allowed to do their work 
freely, what will be the result to the body? 



France and the Liquor Problem. On the eighteenth of 
December, 1902, in the city of Paris, France, a report 
was made by a committee of the government. The state 
officials considered this report so valuable that they 
ordered copies of it to be printed as posters in large 
black letters on a white background. 

These posters were placarded here and there on the 
important buildings of the city. They were put on the 
walls and in the corridors of hospitals, on the streets, 
in the post offices, and even on the outside wall of the 
great Hotel de Ville, where the business of the city 
is carried on. 

A few extracts will show what it was that the govern- 
ment wished to proclaim in this public way. 


Professor Debove, Dean of the Faculty of Medicine 
Dr. Faisans, Physician to the Hotel Dieu 

Alcoholism is chronic poisoning, resulting from the habitual use of 
alcohol, even when this is not taken in amounts sufficient to produce 
drunkenness. Alcohol is useful to nobody, it is harmful to all. It leads, 



at the very least, to the hospital, for alcoholism causes a great variety 
of diseases, many of them most deadly. It is one of the most frequent 
causes of consumption. Typhoid fever, pneumonia, or erysipelas, which 
would be mild in a sober individual, will rapidly kill the alcoholic. 
Alcoholism is one of the most frightful scourges, whether it be re- 
garded from the point of view of the health of the individual, of the 
existence of the family, or of the future of the country. 

After the beginning of the great war in 1914 France 
went even further, and absolutely prohibited the manu- 
facture and sale of the intoxicant, absinth. 

The German Attitude. Nor does France stand alone in 
this protest. Even as long ago as 1908 Germany had 
already printed 871 books that discussed the question of 
alcohol. At that time 37 German newspapers, maga- 
zines, and annuals devoted themselves to the same sub- 
ject, and hundreds of articles about alcohol were printed 
in the important magazines of that country. In 1907 
one hundred leading professors in German universities 
signed a declaration which included the following 
statements : 

All prevalent ideas in regard to the invigorating and otherwise sup- 
posedly beneficial properties of alcohol in small doses have been proved 
erroneous by scientific research. Moderate drinking has a tendency to 
make the human body more liable to disease and to shorten life. 

With this testimony before them, we are not surprised 
to learn that in 1 9 1 5 — for the sake of guarding German 
soldiers and German workmen from inefficiency — the 
supply of beer in Germany was cut down 60 per cent 


Russia and Prohibition. In Russia, in 19 14, when the 
war began, orders were issued that thenceforth there 
should be absolute prohibition of alcoholic drinks. This 
meant that in a country where 150,000,000 people had 
been using all the liquor they cared to pay for, no more 
should be either manufactured, bought, or sold. In de- 
scribing what was done, Professor Helenius Sepala of 
the University of Helsingfors, Finland, says: 

On the sixteenth of October, 19 14, all the old stock of ale in the beer 
shops was, by order of the authorities, poured out on the ground. . . . 
Everywhere in Russia, including Siberia, the Caucasian provinces, Cour- 
land, etc., the sale of distilled liquors and strong wines is strictly pro- 
hibited. ... I walked about the capital one day after another, stepping 
into restaurants both in main streets and in side lanes, and feeling like a 
dreamer because the sights I had formerly seen everywhere in the 
Russian capital I now no longer saw. ... I did not see drunken men 
and women, I did not find whiskey or vodka anywhere. There were 
great festivals going on, the streets were filled with people overpowered 
by their patriotic emotions, it being the birthday of the czarevitch, but 
all the time I did not see a single person the worse for liquor. 

Another writer says : 

On account of this prohibition, crimes have diminished so much in 
Russia that the planned building of new prisons has had to be inter- 
rupted. Physicians tell us that the number of patients in the hospitals 
has decreased considerably and that the alcoholistic polyclinics in Petro- 
grad are now practically without anything to do 1 On the other hand, 
the officials of the savings banks have been compelled to ask for increase 
of their number, in some places double, on account of too much work, 
and the number of depositors has, in spite of the war times and unusual 
difficulties, increased enormously. 


The English Method. In England they are trying to 
reduce the consumption of Uquor by greatly increasing 
the taxes on it and by giving the government full power 
to control the saloons in places where war material is 
being produced and transport work done. 

The Japanese Liquor Law. In Japan the law of the 
land forbids the sale of alcoholic drinks to those who 
are under twenty years of age. 

The Movement in America. In the United States of 
America, in 191 5, 520 daily newspapers and 63 impor- 
tant magazines refused to print any advertisement of 
whisky, beer, or other alcoholic beverage, and the num- 
ber of such papers increases with each month. These 
statistics were gathered by the Temperance Society of 
the Methodist Church. 

In 191 5 the new rule of the Carnegie Steel Works, 
Pittsburgh, Pennsylvania, declared that promotion was 
only for total abstainers. In 191 5, also, the head of 
the Health Department of New York City declared 
that the entire power of the board would be used 
to "fight the rich man's champagne as well as the 
poor man's beer." The statement was then made 
that "it is as necessary to battle drink as to fight an 

The United States Department of Labor has investi- 
gated the subject of alcohol in connection with the em- 
ployers of skilled labor. It finds that already 72 per 


cent of the farmers, 88 per cent of the trades, and 
90 per cent of the railroads make positive discrimi- 
nation against the man who uses alcohol. For ex- 
ample, Marshall Field and Company, of Chicago, say: 
" Any man in our employ who acquires the habit of drink, 
even though moderately, is to a certain extent marked 
down in our estimation, and unless we can remove from 
him this serious fault and show him his error, we feel 
compelled to do without his services." Employers of 
labor discriminate in this way because they cannot 
afford to pay for the services of a man who is below par 
physically and mentally. 

And what of skilled laborers themselves? On May 25, 
191 5, in Cleveland, Ohio, the Brotherhood of Locomotive 
Engineers passed the following resolution by unanimous 
vote : " Be it resolved that this Brotherhood of Locomo- 
tive Engineers go on record as favoring state-wide and 
nation-wide prohibition of intoxicating beverages." There 
were present 8 1 9 delegates, who represented 74,cxx) engi- 
neers in all parts of the United States and Canada. After- 
wards one of them said : " Engineers of America have 
been trained for years to understand that drink and 
efficiency do not run hand in hand. If any one needs a 
clear head it is the man in the cab." 

Nor is this all. Great nations and great bodies of 
voters are not the only ones who are voting themselves 
free. Smaller nations are equally anxious for safety. 


The Island of Newfoundland. During December, 191 5, 
Newfoundland voted four to one in favor of prohibition 
for the entire island. The count stood 24,965 votes for 
prohibition and 5348 votes against it. 

Taxes, Crime, and Poverty. No doubt thousands of 
citizens in every land have in mind the taxes which they 
must pay to help support the poorhouse, the courthouse 
and jail, the reformatory, the insane asylum, the orphans' 
home, and the police force of every state and city. In these 
days we all know that the larger part of the occupants of 
these institutions are where they are because they them- 
selves or their ancestors used alcohol as a beverage. Mr. 
Henry M. Boies, who studied the subject for years in 
America, said that the crime committed in the United 
States costs at the rate of $6.20 a year for each man, 
woman, and child in our country, and that alcohol's share 
in the expense of this crime is about $4.34 for each 
person. Drunkenness alone, he tells us, costs the United 
States ^420,000,000 a year. 

Statistics for London, England, show that this one city 
pays $5,000,000 a year for the expense of its drunken 

To show the difference which alcohol makes in the 
taxes of license and no-license towns, glance at the fol- 
lowing figures. They are compiled from the reports of 
the United States Bureau of the Census on municipal 
revenue expenditures and public property for 191 3. 



Prohibition states . . $10.12 per capita 

Near-prohibition states $11.08 per capita 

Partially license states $14.32 per capita 

License states $16.98 per capita 

When you see a drunken man arrested, or read of men 
taken to jail or to the hospital because they have dam- 
aged themselves or other people by using alcohol, you 
might say to yourself, '' My honest, hard-working father, 
through his taxes, helps pay for arresting the man, for 
trying him, for taking care of him in prison, for feeding 
and clothing him while he is there; and if the man 
dies in the place, my father must help meet the bill for 
his burial." 

Fortunately the entire world is wakening to the serious 
harm which alcohol does to society in every way, and 
this explains the dawning era of prohibition. 


1. Tell how Paris began to attack its liquor problem. 2. When did 
France prohibit the manufacture and sale of absinth? 3. What had 
Germany done before 1908 about the alcohol question? 4. What decla- 
ration did the leading professors of Germany make ? 6. How much was 
Germany's beer supply cut down in 19 15 ? 6. What orders were issued 
in Russia in 19 14? 7. How many people did these orders affect? 

8. What did Professor Sepala say about the results of this action? 

9. W^at effect did prohibition have on prison building? on the number 
of patients in the hospitals ? 10. What did England do to reduce liquor 


consumption ? 11. What is the liquor law in Japan ? 12. Tell what you 
can about liquor advertisements in papers and magazines in the United 
States in 19 15. 

13. Give the rule of the Carnegie Steel Works about promotion. 
14. When the United States Department. of Labor investigated the sub- 
ject of alcohol in connection with the employers of skilled labor, what 
did it find? 15. Why do employers of labor object to those who use 
alcohol? 16. Give the resolution of the Brotherhood of Locomotive 
Engineers. 17. What was the result of the vote on prohibition in 
Newfoundland ? 18. Why are taxes high in countries that use alcohol ? 
19. What sends many people to the poorhouse, the jail, the insane 
asylum, and the orphans' home ? 20. Give Mr. Boies' statement about 
the cost of crime in the United States. 21. What is London's annual 
expense for drunken paupers ? 22. What is the difference between prop- 
erty taxes in prohibition states and in license states ? 23. In what way 
does every honest man help support those who are criminals and worthless ? 




Testing the Effect of Heat on the Body. There is no 
doubt about the value of the work which certain scien- 
tists did in 1775. These men were anxious to know how 
much heat the body of man can endure and still keep at 
its work. For the sake of making no great blunder, they 
began their tests by passing from one heated room to 
another until they found themselves living and breath- 
ing in a room in which the thermometer showed a heat 
of 210° F. This is but two degrees cooler than the 
temperature which water needs for boiling. 

As may be imagined, the air of the room felt very 
hot. One man, however, stayed in it for ten minutes. 
During this time the heat was so great that it twisted 
and broke the ivory frames of all the thermometers but 
one. More than this, the air which the man inhaled was 
so much hotter than that which he exhaled, that with 
each breath which he drew he felt as if he were scorch- 
ing his nostrils. But with each exhalation his nostrils 
were cooled again. He took the thermometer in his 

hand and blew on it. At once the mercury sank in the 



tube, showing that his breath was cooler than the room. 
He blew on his fingers, and they were cooled top. 

In another experiment, afterwards, the same men went 
into a small room which was even hotter than any 
they had been in before. Here the thermometer showed 
260° F. This, then, was forty-eight degrees hotter than 
water needs for boiling. As they entered the air felt 
hot, but they could bear it. And while they stayed there, 
they did various things to show what the heat of the 
room was able to accomplish. They took a piece of raw 
beefsteak, left it uncovered, took a pair of bellows, blew 
the heated air across the steak for thirteen minutes, 
and found that it was rather overcooked. An egg was 
roasted hard in twenty minutes; water soon boiled and 
bubbled; watch chains became too hot to be touched; 
and rings had to be left off, lest the heated metal should 
burn a deep circle about the tender flesh of the finger. 
Leather shoes could not be worn, for the leather itself 
curled up and was ruined. 

Sweat Glands as Protectors. All this happened to 
their possessions, but the men themselves, although 
surrounded by the same heated air, were neither boiled 
nor roasted. They lived and breathed in the place, 
escaped alive, and their escape was no miracle. It was 
explained by the power of the sweat glands. If these 
small laboratories had stayed inactive the scientists 
might have suffered from the heat even as did the steaks 


As soon as the men entered the heated room the 
sweat glands began their work and perspiration was manu- 
factured in quantities; it poured from the open flues of 
countless small laboratories and emptied itself upon the 
skin, whence it was evaporated. Thus 
perspiration kept the skin moist, and the 
evaporation of the moisture kept the sur- 
face of the body cool enough to save it 
from being cooked. Certainly the men 
were uncomfortable from first to last, but 
they did not suffer. 

The record of these experiments is 
given in the Philosophical Transactions 
of the Royat Society of London for the 
year 1775. 

If you ever have the chance, watch the 
streaming, steaming backs of such men 
as pitch coal into the huge furnace of an 
A Sweat Gland occan liner. There you will see the same 
AND ITS Outlet ^grk of protection Carried on by these 
tireless glands. Their exact number is 
unknown, but by counting a few in a small area of the 
skin, and by multiplying this number by the extent of 
the surface of the body, men estimate that each of us is 
supplied with about 2,cxxi,ooo sweat-gland laboratories. 
All are slightly busy most of the time, but are only ex- 
traordinarily busy when emergencies overtake the body. 



Important Facts about the Skin. Just here, review 
your knowledge of the skin and of perspiration. 

1. The outside layer of the 
skin is called epidermis. It can 
be cut or pricked without giving 
pain. It protects all that lies 
underneath it, in the second 
layer of the skin. 

2. The second layer — the der- 
mis — holds countless capillaries, 
also nerve fibers, hair cells with 
their muscles and oil glands, 
sweat glands, and pigment cells. 
These last contain coloring mat- 
ter — pigment — which gives one 
boy freckles and another boy tan ; 
which makes one man brown and 
another man yellow. Both nails 
and hair are constantly being 
fonned in the dermis and pushed 

3. Perspiration is a mixture of 
water and waste. It is poured 
out by the sweat glands when the 
body is heated or exercised. The 

A, horny layer of epider- 
mis; B, deeper layer of 
epidermis ; C duct of 
sweat gland; D, dermis; 


water soon evaporates and cools the skin. The 
waste stays on the skin and must be washed or 
rubbed off; otherwise it mixes with oil from the 
oil glands, with bits of epidermis, with dust from 
the clothes and from the air, and stays like a snug, 
thin, perfectly fitting coat on the outside of the 
body from head to heel. A wrap of this sort inter- 
feres with the healthy action of the skin and gives 
off an unpleasant smell. It may Be removed by a 
hard, dr)'^ rub, and it is important to take the rub 
whenever a bath is out of the question. 
What the Skin Does. The skin does four most impor- 
tant things for us. 

1. It covers the body as a wrapping without a 
break in it. Thus it keeps multitudes of microbes 
from entering. When a patch of skin is entirely 
destroyed by being scalded or burned, there is such 
power of life left along the edges that new skin 
grows out from it day by day until the chasm is 
entirely covered — provided it is not too large. If 
it is too large, doctors step in with their wonderful 
help from grafted skin. By what they do they may 
save the person from being badly scarred. 

2. By means of its sweat glands it helps regulate 
the heat of the body and keeps it at uniform tem- 
perature throughout life. No device of nature is of 
more practical service to us. 


3, It forms the ground against which nerves act 
and through which we do our feeling. Most of our 
impressions of heat and cold, of pain and suffering, 
reach us through the skin. 

4. It helps the lungs and the kidneys in their 
work of sending waste from the body. Perspiration 
is waste matter that is being eliminated. 

For each of us, however, there is something far more 
important than hot ovens, burned flesh, and the graft- 
ing of the skin. It is not probable that we ourselves 
shall meet these terrible experiences. For us a practical 
everyday danger is always at hand. 

Taking Cold. We may take cold through our igno- 
rance of the laws that govern the health and vigor of the 
skin. Let us therefore remember that the skin is con- 
stantly covered with a slight moisture called insensible 
perspiration, and that when there is enough of this 
moisture to be noticed it is called sensible perspiration. 
One advantage of perspiration is that it cools the body 
whenever it is in danger of getting overheated. For 
the sake of grasping the situation more clearly, bear the 
following facts in mind : 

1. When a man is heated from exercise, capillaries 
in the exercised part of the body are stretched out 
with the blood which is forced into them. 

2. If a heated man, covered with perspiration, sits 
in a draft, his blood is cooled, the capillaries of the 


skin contract, and the mass of the blood goes to 
some other place. 

3. When this occurs, the linings of nose,- throat, 
lungs, and intestines are apt to be overcrowded by 
the blood which has been forced into them from the 
skin, and the most sensitive lining suffers most. 
Symptoms of a Cold. Usually the first symptom is that 
a man feels stuffy in nose, throat, or lungs. The explana- 
tion of the feeling is the distended capillaries and the 
condition of the blood itself. Although red corpuscles 
continue to deal with oxygen as they have always done, 
still the white corpuscles are now behaving strangely. 
They get together, many of them stick to the inside 
walls all along the length of the capillaries, and the more 
inactive they are, the less do they seize and destroy 
intruding microbes. These microbes, therefore, remain 
uncaptured in the blood and continue such mischief 
as their nature makes possible. 

When a man has a cold, the trouble often is that 
influenza microbes have escaped the white corpuscles 
and have firmly established themselves in the part of 
the body which is congested with blood. 

In view of these facts it is not hard to understand why 
a man who has a cold is so much more liable to take 
other diseases to which he is exposed. He is in a weak- 
ened condition, and already microbes instead of white 
corpuscles have the upper hand in his body. 


But suppose a cold is coming on, what does our knowl- 
edge of the laws of the skin direct us to do about it ? 

To Check a Cold, Draw blood away from the region of 
the cold as promptly as possible. Do it in several ways : 
take vigorous exercise until every sweat gland is active ; 
take a hot bath; soak the feet in hot water; drink hot 
lemonade; go to bed; sleep warm; perspire freely. By 
keeping warm in bed, the blood goes to the surface of 
the body, and delicate internal membranes are relieved 
of superfluous blood. White corpuscles are also stirred 
up, and restoration begins. Stay in bed until the feeling 
of cold is over. One night may suffice. When you leave 
the bed, wipe off with warm water, then take a quick 
wash with cool water. This will stimulate the nerves 
of your skin without chilling the blood itself, and will 
keep you from taking cold afterwards. 

To Prevent a Cold. Here are three rules of prevention 
that you should remember : 

1. Never sit in a room that feels chilly. A long 
slow chilling of the body does even more harm 
than a draft. 

2. Never come in heated from hard exercise and 
cool off in a chilly room. Multitudes of colds are 
taken in this way. Either continue to exercise in the 
room, or wrap up thoroughly. Best of all, take a 
quick, cool bath in a warm room and change your 
damp underwear before you sit down. 


3, Remember that there is little danger of harm 
to health, however damp the clothing may be, so 
long as vigorous exercise is kept up. 

4. Obey all the general laws of eating, exercise, 
etc., and follow the instructions on page 207 about 
educating the body to adjust itself. 

The reason for all this is that bodies are provided 
with the extraordinary power of regulating their own 
temperature by means of fuel and work. 

Internal Temperature. Let a man live in central Africa 
or let him travel to the coldest land; let him stay in 
the burning heat of his city home or wander in the 
cool shadows of the country; let him be in bed or in 
the harvest field, in the countinghouse or in the mine; 
wherever he is, he will find that, if he is well, a ther- 
mometer placed under his tongue always indicates about 
ninety-eight degrees of heat. This is what we call normal 

In each place, also, even if he is not well, the heat of 
his body will change but little. We say that a man has a 
slight fever if his temperature is 100° F. If it reaches 
102°, we grow somewhat troubled; if it rises to 103° and 
then to 104°, we are truly anxious; for no man is ex- 
pected to live after his temperature has reached a higher 
point than 107°. 

It is well for us that the body has this power to keep 
the blood warm independent of outside conditions ; for if 


it were otherwise, — if we were as cold-blooded as is the 
frog, — we should be as useless in cold weather and in 
cold places as he is. We should have to hibernate in 
winter as he does. 

Warm-blooded Animals. Birds, as well as all animals 
that begin life by taking milk from their parents — mam- 
mals they are called — are warm-blooded. Each has for 
itself this wonderful power of meeting the changes of 
the weather with a constant temperature of its own. As 
a result, such animals are generally warmer than the sur- 
rounding air and are called warm-blooded for this reason. 

Cold-blooded creatures usually feel cold to the hand 
when we, who are warm-blooded, touch them. Their 
bodies have no power to stay warm when the air is 
cold about them. 

Although we have this power, it is nevertheless true 
that even the heat of our warm bodies can fail. Men do 
freeze to death. They cannot be frozen almost solid and 
then thaw out again and live, as certain frogs have been 
known to do. People may live in the coldest countries 
and be active and healthy there, but the one condition 
is that they help the body do its work by preventing the 
escape of more heat than the same body can promptly 
replace. Never confuse these two facts: 

I. During health the inside heat of the body 
changes little from years end to year's end. If it 
changes many degrees up or down, we die. 


2. The skin feels warm or cold as the air about it 
changes. Skin and nose and toes may freeze, but the 
inside temperature remains practically unchanged. 
Why Clothes are Needed. Put a dozen people in a 
small room, and the room grows warmer because 
those human beings give off enough heat to warm 
the air about them. In a cold country or in a cold 
room each body must keep within itself as much of 
its own heat as it can. Naturally, therefore, we wear 
more clothes at one time than at another. We are 
treasuring up our own supply of heat for our own 
use, and we know that we lose this heat largely from 
the surface of the body — from the skin. We there- 
fore wrap up. Do not forget that we are warmed not 
by the cold we keep out but by the heat we keep in.^ 
Flannel succeeds better than cotton in preventing the 
escape of heat, because more air is entangled in the 
mesh of woolen goods than in a cotton fabric. This air 
keeps the heat from passing from the body, because air 
is what is known as a poor conductor of heat. For this 
reason we choose woolen goods for winter wear and 
cotton materials for summer. 

1 If the body is not sufficiently covered, heat radiates from it and escapes. 
Cool air takes its place at once and surrounds the body as a layer. Capillaries in 
the skin now contract and force the blood away from the surface to the inward 
parts of the body. These parts then become congested, while the skin feels cold, 
because the contracted blood vessels can only hold a small supply of blood. By 
putting on extra clothing and by rubbing the body hard, we cause blood vessels 
in the skin to expand, more blood passes through them, and we are warm ag^ain. 


Moreover, each additional layer of clothing means 
an extra jacket of air underneath it. And since air is 
a poor conductor of heat, several layers of thin gar- 
ments — with their separate layers of air between them 
— are often a warmer protection than one thicker 
garment with its one layer of air underneath. 

In summer we choose the thinnest clothing and the 
fewest possible layers of it. We wish to make it 
easy for heat to escape. Nor is clothing our only 
warming device. 

Warmth through Exercise. Why do boys say, " It's 
so cold we've got to run to keep warm"? For this 
reason — when muscles contract and when blood moves 
fast, the heat of the body is decidedly increased. Vigor- 
ous exercise of large muscles increases the heat of the 
blood. Then, as this blood reaches the skin, it is cooled 
by the evaporation of the perspiration. Our body has 
two ways by means of which it controls heat escape: 

1. By regulating the flow of blood into the skin. 

2. By the sweat glands and what they do. 
Food as Fuel. Consider that while you exercise you 

breathe hard and expel warm air from your lungs. 
This comes from heat produced by your body while 
it works. And what is the source of its power both 
to work and to produce heat? Watch yourself at the 
dinner table after exercising. You have such an appe- 
tite as comes only when you have been using up 


your supplies. Food is to the body what fuel is to a 
stove, and in a certain way your machine has been 
burning up its fuel while you worked and grew warm. 
Your appetite is nature's call for a fresh supply of food 

Sometimes active exercise leads the body to call for 
so much fuel that the stored-up supply — fat — is rapidly 
reduced. Any football player will tell you that during 
the football season he loses fat which he gained during 
the previous summer. 

To Reduce Fat. The body has need of extra fuel when 
it does unusual work, and it then draws on its reserved 
supply. A fat man applies this power of the body to his 
own case. He studies himself both in the mirror and on 
the scales and concludes that his body has stored up too 
much fuel in the shape of fat. He knows that to get rid 
of it he must use it, and at once he begins a course of 
vigorous exercise which gives hard work to large mus- 
cles. They respond by calling for fuel, and if he is faithful 
day after day, the mirror and the scales will soon show 
that he is accomplishing his purpose — that he is losing 
his fat. 

Perhaps we wonder how it happens that although we 
sometimes exercise so hard as to use up much of our 
fuel, the thermometer shows a gain of so little bodily 
heat. As we already know, the reason rests partly with 
the sweat glands. They are such a successful cooling 
device that whenever we exercise enough to raise our 


temperature above its normal point, they promptly manu- 
facture their clear-colored liquid. And when once manu- 
factured, they send so much of it out upon the skin to 
evaporate there that, no matter how warm we feel, the 
internal temperature of the body is kept from rising 
too high for safety. 

The body is thus seen to produce its own heat, while it 
also cools itself when we overheat it. Through this power, 
however, we may take cold unless we know how to pre- 
vent heat from escaping too fast when the body needs it. 

Educating the Body to Adjust Itself. We may so train 
the body that it will increase its power to adjust itself 
to different states of heat and cold. In other words, the 
body can be educated. This may be done by following 
the rules about eating and exercise already given and by 
attending to a few other points. 

1. Do not spend much time in overheated rooms, 
that is, in places heated above 70° F. The body 
grows exceedingly sensitive to cold if it is kept 
constantly too warm. 

2. Do not overweight yourself with clothing in 
a warm house or take vigorous exercise in heavy 
garments. In other words, regulate your clothes to 
your need. 

3. If you are in good health, take a quick cold 
bath every morning. Nothing is better for prepar- 
ing the blood vessels for changes in temperature. 


Don't run about with bare feet and get chilled be- 
fore this early bath« The body should be warm for it 
Never give a cold body a cold bath. Never take a cold 
bath in a cold room. Let the room be as warm as 
70°. It maybe even warmer. Let the cold bath be 
short — one minute is long enough. You are using 
the water for a tonic, not for a scrub. Use two 
rough towels, one wet and one dry. Wet face and 
neck first, then arms, chest, abdomen, back, legs, and 
feet. If you have no bathtub or shower bath, take 
a washbowl of water, and wash and wipe one part of 
the body after the other quickly in the order given. 
(The shower bath also goes from the neck down- 
wards.) Waste no time. Rub fast and hard until the 
skin is pink. The body will glow with a feeling of 
warmth and vigor. If it does not glow, — if it is cold 
instead, — then you are not quite vigorous enough 
to take the cold bath. You must get stronger first. 

4. Keep the body clean by taking a soap-and- 
water bath at least once a week. 
He who attends to the various rules connected with 
bathing, eating, exercise, and the heating of the body 
will find at last that he has reached the happy condition 
where sudden changes in temperature and unexpected 
drafts do not harm him as they did in former days. 

We see, then, that the real purpose of hygiene is to 
help the body as it tries to help itself. In reality, food, 


muscles, blood vessels, and sweat glands work together 
for the regulation of body temperature. At the same 
time the central regulator of all their activity is the 
nervous system. To this we now turn our attention. 


1. What were scientists trying to learn about the heat of the body 
in 1775 ? 2. Describe the way they tested the human body in heated 
rooms. 3. How hot was the air? 4. What happened to beefsteak, 
eggs, water, and watch chains that were in the same room? 6. How 
did the men feel? 6. What saved them from being cooked? 7. When 
are the sweat glands most active? 8. How many sweat glands is a 
human being supposed to have? 9. Describe the epidermis. 10. De- 
scribe the dermis and tell what is in it. 11. Describe perspiration. 

12. What things are mixed with perspiration on an unwashed skin ? 

13. What four things does the skin do for us? 14. From what part 
does new skin grow to cover a wound? 15. When is skin-grafting 
necessary ? 

16. What is insensible perspiration? 17. What is sensible perspira- 
tion ? 18. What is the purpose of perspiration ? 19. When a man is 
heated, what happens to the capillaries ? 20. If he sits in a draft, what 
then ? 21. What is generally the first symptom of a cold ? 22. Describe 
the behavior of the white blood corpuscles at such times. 23. Why is a 
man who has a cold more liable to take other diseases ? 24. If you feel 
a cold coming on, what should you do to check it ? 25. Give three rules 
for preventing colds. 26. What can you say about the heat of the body 
in different countries? 27. What is our normal temperature? 28. De- 
scribe warm-blooded and cold-blooded creatures. 29. What can you say 
about the inside heat of the body ? 30. Why does a room grow warmer 
when people are in it? 31. Why should we wear more clothes at one 
time than at another? 32. From what part of the body do we lose 
heat? 33. Why is flannel warmer than cotton clothing? Why are 


several layers useful? 34. Are we warmed by the cold we keep out 
or by the heat we keep in? 

36. How does exercise keep us warm ? 36. In what two ways does 
the body control the escape of heat? 37. What connection is there 
between food and the power of the body to heat itself by exercise? 

38. When much exercise is taken, what stored-up fuel is drawn upon ? 

39. What may a fat person do to change his appearance ? 40. How can 
you explain the fact that hard exercise has litde effect on the inside 
temperature of the body ? 41. Since the body can cool itself when it 
is too warm, what is the danger in being overheated? 42. Give four 
rules for helping the body to adjust itself to heat and cold. 43. What 
is the real purpose of hygiene ? 



The Value of Sensations. If a cat felt no unpleasant 
sensation when he needed food, he would never bestir 
himself from a comfortable nap for the sake of eating. 
If a mouse felt no unpleasant sensation when the claws 
of a hungry cat were hooked into his skin to seize him, 
he might allow himself to be caught and eaten without 
a struggle. If human beings felt no discomfort in the 
coldest weather, they might carelessly let themselves 
be frozen to death. 

The Hedge of Nerve Warnings. So it is on every side. 
All along the way we go, our sensations are our best 
protectors. Indeed, during each day of our lives our 
animal kindred and we ourselves travel through life 
over a road that is guarded on either side by what 
might seem to be a hedge of nerve warnings called 
sensations. The sensations themselves are of various 
kinds, hunger and thirst, cold and heat, headache, tooth- 
ache, stomach ache — ills of many different sorts. But 
through each separate one we learn at last that by 
giving heed to our sensations — to those that are 



disagreeable as well as to those that are agreeable — we 
do much to preserve our health and to make the path- 
way of life safe and 

What Nerves are. Be- 
fore the microscope was 
invented even the very 
wisest men had to do 
much of their scien- 
tific work by guessing. 
They imagined that 

One Set ok Fibers at Work ^^y^ ^^^^ ^^S ^ tU^g 

filled with something exceedingly fine and delicate 

called animal spirits. But in recent times, guessing has 

been discarded. For the 

microscope shows that 

nerves are not tubes 

at all. Instead they are 

a system of fine fibers 

which carry stimuli and 

messages back and 

forth between the other 

parts of the body 

and the brain. These 

Another Set of Fibers at Work 

fibers look like slender 

threads. They run from the brain to the spinal cord, 

from the cord to the muscles, then from the muscles up 


again to the spinal cord and the brain. Just under the 
skin these fibers cover the body in a close network, and 
it is through their aid that living beings feel, and move, 
and control their actions. 

Work of the Fibers. More than this, it is well to know 
that nerve fibers are divided into two groups which do 
two kinds of work. One group carries stimuli to the 
brain from skin, eye, ear, nose, tongue, and from all the 
internal organs of the body. These are called sensory 
nerves. The other group carries commands from the 
brain to every point in the body that needs directing. 
These are the motor nerves. 

When a baby sees a flame, laughs with joy, thrusts 
his fingers into it, and pulls them out again with a 
scream, several sets of fibers have been at work. 

1. One set, from the eyes, helped the brain to see 
a lovely color. 

2. Another set brought word from the brain to 
the muscles of the hand, " Feel it." 

3. A third set carried a stimulus to the brain, 
which seemed to say, " Something dreadful is 
happening to the fingers." 

4. A fourth set brought the prompt command, 
" Pull the fingers out of the color as fast as 

Different Sets of Fibers. In the meantime other groups 
of fibers set other muscles to work, so that at one point 


the baby opened its mouth to laugh with joy and a 
moment later opened it again to scream with pain. Still 
other fibers commanded the heart to pump faster and 
send more blood to the excited head. They commanded 
the tear glands to manufacture salt water with incredi- 
ble speed and in great abundance. They set lungs and 
vocal cords to work, too. And as the result of so much 
stimulation sent up to the brain and so many commands 
sent down from the brain, we end with a nervously 
exhausted, screaming, red-faced, tear-stained baby, rather 
a dejected-looking piece of living machinery. 

Stimuli. If we could ever follow any series of mes- 
sages up and down, we should learn to understand how 
swift their flight is. Stimuli from remote regions of the 
body fly upward to the brain, and there, in what is really 
the great central station, the various kinds are recog- 
nized and attended to. Commands are issued at once, 
and each of these now goes by its own road downward 
to the spinal cord. From there it is flashed across an 
unbroken long-extended * fiber to a toe, or a finger tip, or 
to any muscle of the body that is to be controlled by it. 

The longest fibers are those which carry an impulse 
from the toe up into the spinal cord and those which 
bring commands back over the same distance. In a tall 
man these fibers, carrying messages in one direction or 
the other, may be four or five feet long. And their work 
is as perfect as that of any short fiber. 


Distribution of Nerves. If by any clever process we 
could separate the nerves of a man from the rest of his 
body, if we could turn each one of these nerves into 
something stiff and firm, 
and then could stand the 
entire group on a pedestal 
in precisely the shape which 
it had when it did its work 
in the body, we should un- 
derstand better than we do 
the marvel of its structure. 
This network of stiff nerves 
would be so delicate and 
so closely woven together 
that we should be able to 
follow perfectly the outline 
of the man to whom it be- 
longed. We should know 
his height, the breadth of 
his shoulders, the size of 
head, hands, and feet ; while 

at the same time we should nerves that show the outline of 
note that on certain parts the human body 

of his skin the network was specially fine and delicate. 

If, going further, we should cut that nerve figure 
open, we should find other great clusters of nerves that 
showed the outline of every separate organ of the body. 


Having seen all this, unless we know the facts of the 
case, we might give a thousand wild guesses as to what 
this wilderness of nerves was for and how it was ever 
able to control the sensations and the movements of a 
human being. Some knowledge of the working of the 
brain will help explain the difficulty to us. 

Memory and the Cerebrum. Dr. W. H. Howell, in his 
physiology, describes the case of a dog who met with mis- 
fortune, lost the upper part of his brain, — the cerebrum, 
as it is called, — and led a singular life ever afterwards. 

Those who were studying the case kept the dog alive 
a year and a half, and they saw that although the animal 
did not suffer actual pain, still he did not know enough 
to feed himself ; he did not even recognize his food when 
he saw it; he showed no pleasure when caressed nor 
any fear when threatened. Not a trick that he had ever 
learned did he now remember. And as for burying 
bones for future use, there was no thought of such a 
thing. Indeed, from the moment he lost his cerebrum, 
until he died, he seemed to do no thinking whatever. 
Memory was so entirely gone that he recalled nothing 
that he had ever learned. Formerly he had been a 
clever and sprightly dog, remembering old tricks, learn- 
ing new ones, stealing bones and burying them, frighten- 
ing cats, loving his friends, and fighting his foes; but 
from the moment he lost his cerebrum all was changed. 
Henceforward he was dull, inactive, and uninteresting. 


In man the cerebrum is even more important He 
may lose part of it through disease or accident and still 
be able to live and think, but if he loses the whole of 
it, he dies. If it is injured he suffers in various ways. 
It is the region of 
the brain that is 
most vitally con- 
nected with our 
thinking, with our 
activity, and with 
our power to judge 
what is best for 

This constantly 
active and most im- 
portant part of the 
nervous system lies 
just under the skull. 
It is the largest di- 
vision of the brain, 
and is separated 
into two halves called hemispheres, as shown above. 

Structure of the Brain. If you ever have a chance, take 
in your hands a human brain that has been preserved 
in alcohol and let a doctor describe it to you. First of 
all, however, you will notice that the substance itself 
looks like nothing so much as a neatly folded, closely 


packed mass of gray putty, so lifeless and so uninterest- 
ing that you may feel like exclaiming: " Is this the great 
commander in chief of the body of man! Is this queer- 
looking stuff the basis of all my thinking and my 
feeling ! " 

But let the doctor hold it and explain it to you 
part by part. Watch his eyes; listen to his voice as 
he does it; for they will tell you that to him this 
lifeless mass is interesting in every smallest division. 
He will press one part away from another at the 
surface, and you will see that although each can be 
separated slightly from its neighbor, still all are 
firmly held together at the center. 

He will show you the cerebrum and another division, 
called the cerebellum, and will probably mention them 
in that order, for the cerebrum is larger and higher up 
— a soft gray cap, it seems to be, folded closely in deep 
creases, overlapping everything below it. Nevertheless, 
the cerebellum is in sight just beneath, at the back of 
the head. It too is folded and wrinkled and gray. 

Cerebrum, Cerebellum, and their Convolutions. It may 
be that you will ask some questions about these deep 
creases in both cerebrum and cerebellum, — convolu- 
tions, they are called, — and it may be that the doctor 
will answer very thoughtfully, " The more wrinkles, the 
more wits," for that states the case concisely. " But 
what good do the convolutions do?" you ask again. 


" Give more surface for the gray stuff to be spread 
over," comes back the answer, quick and positive. And 
this answer leads the doctor up to the point of his 
greatest enthusiasm, the gray substance of the brain. 

A Cut 

A, B, C, D, L show folds in the cerebrum ; E, F show the gray and white of 
the cerebellum ; K, H show the upper divisions of the spinal cord 

The Gray and the White Brain Stuff. Gray substance 
is all you have seen thus far, for it bends in and out 
with every fold and crease as if the whole substance of 
the brain were solid gray. " But look here," exclaims 
the doctor, as he presses open a deep cut which he 
has made with his knife through the gray cap, " see 


how little gray there really is — only an outside layer 
about an eighth of an inch thick and thinner than 
that in spots. But every thought you have, every 
pain you feel, every plan you make, every hope that 
thrills you, every purpose and ambition of your life, 
is intimately connected with this thin gray layer that 
covers the white substance below it" 

While you are thinking this over in amazement he 
will probably go on to say that the injury or disease 
of any part of that gray layer of the brain may rob 
you of one sense or another, or even destroy your 
brain ppwer in the very direction where you thought 
you were strongest. 

Centers in the Cerebrum. *' If this particular brain had 
been injured here," the doctor will say, pointing to a cer- 
tain spot on the gray surface, " its owner would not have 
been able to recognize anything that the eye looked at. 
And this is the worst sort of blindness, for when the 
sight center of the cerebrum is gone a man cannot so 
much as remember what seeing was like." 

Accidents to the brain have taught some of these 
facts; diseases of the brain have taught others; while 
the study of the brains of animals has let in a flood 
of light on the whole subject So that at the present 
time scientists know that a definite part of the gray 
layer is active for each separate sensation and for 
the power to move each separate part of the body. 



How the Sktill protects the Cortex. This layer is called 
the cortex, and cortex means "bark." It is clear then that 
the gray bark that covers both cerebrum and cerebellum 
is the most precious 
part of the human 
body. For this reason 
it needs a stout pro- 
tection, and it gets it 
in the firmly knit, 
sturdy skull which 
surrounds it. 

Instead of being a 
snug fit in its case, 
the brain is separated 
from the skull by a 
little space filled with 
liquid. And it is this 
well-housed brain that 
controls the nerve 
machinery of the body. 

Nerve Machinery. 
From what seems to be 
a confused tangle of 
fibers under the skin, 
we might imagine that messages would sometimes get 
lost on their journey — that those intended for one partic- 
ular spot might find themselves delivered at the wrong 

Roads To and From the Cortex 

Sightf hearings and touch have special centers, 
but taste and smell are near together 


place, bringing despair to the brain. But this never hap- 
pens. The confusion is only apparent ; it is caused by the 
way the bundles of fibers are variously bound together. 
If we had eyes keen enough to see the fibers them- 
selves, instruments delicate enough to do the work, and 
hands steady enough to use the instruments without 
tearing the fibers, we might unwrap them, bundle after 
bundle, and trace them from start to finish. We should 
then find that every 
white nerve is a bun- 
dle of nerve fibers, 
each one of which 
is neatly and snugly 
wrapped by a fatty 

Nebve Fibers that end in Muscle . , , 

covenng that makes 
it look white. We should also find that the difference 
between large nerves and small nerves is quite the same 
as the difference between large bundles and small 
bundles of telephone wires, for in each the number of 
separate strands explains the size. 

Spinal Nerres. As we studied the nerves in this way, 
we should discover for ourselves where the largest ones 
are and how they are related to the backbone. We 
should see that the bones of the back are so ingeniously 
locked together that a round opening is left on each side 
of each pair of vertebrae, and that as there are thirty-one 
vertebne there must be sixty-two openings in all. We 


should then notice that' the largest nerves of the entire 
nervous system are these sixty-two spinal nerves which 
find their way to the body through the backbone, and 
we should see that as soon as each leaves the bone the 
dividing begins. Large bundles, from the cord, become 
smaller by dividing, then still smaller. They hold any- 
where from two hundred to twelve hundred separate 
fibers, and as they continue to divide and subdivide 
they branch in different directions until fibers which 
started in the same bundle are widely separated. 

Often these fibers pass out of the wrappings of one 
bundle into the wrappings of another. They do this so 
constantly that the various bundles, as they grow smaller, 
are joined together in an intricate network. They twine 
and intertwine, but not a fiber loses its way. Each 
tiny one of the millions that form the lacework of fibers 
is a continuous path from some definite point on the 
skin, or from some muscle or gland, to some definite 
point in the spinal cord ; and as long as no accident or 
wound cuts the nerve in two, the stimulus which each 
may receive will travel swift and true from the point 
of the body where that fiber is stimulated to the spinal 
cord, which will send the impulse on to the brain by 
other fibers. 

What Accidents teach us about Nerves, But accidents 
are frequent, and they teach scientists wonderful facts 
about those long nerve fibers. One of these facts is that 


nerves are useful or not, according as they remain un- 
broken. Think of the baby who burned his fingers. His 
nerves of feeling and nerves of motion were in good 
running order; he felt pain and could pull his hand 
away; but if a certain set of fibers had been cut across 
so that the connection was broken, no stimulus would 
have reached his brain. The baby could then have left 
his fingers in the fire until they were burned off, with- 
out feeling the slightest pain. If, on the other hand, 
a different set of fibers had been cut, no command 
could have reached the fingers from the brain. The 
baby would have suffered frightful pain, but he would 
not have been able to move his fingers back or forth 
to get out of trouble. His arm muscles would have 
had to come to the rescue of finger muscles and pull 
the hand away. 

If both sets of fibers had been cut, the baby would 
not have felt any pain, nor would he have been able 
to move his fingers. But the burning would have gone 
on just the same. 

Truthful and Untruthful Messages. The impulse which 
passes over a fiber is always truthful if that fiber is un- 
cut and uninjured from end to end ; but if damage has 
been done, strange reports may reach the brain. Old 
soldiers testify to this. One of these men lives near my 
home, and when we met the other day he said, " Is n't 
it strange, my leg was cut off over ten years ago, but 


last night the heel of that foot itched and pained me 
so that I thought I should go crazy? " " What did you 
do?" I asked. "Put a hot- water bag against the stump, 
warmed the thing up, and finally got relief." Of course 
he knew as well as I did that something was irritating 
the live ends of the fibers that used to send reports 
from the heel to the brain, and that when the brain 
received the stimulus it had no way of knowing that 
the fibers had been cut in two and that their extreme 
ends were no lower down than the knee. The thinking 
and seeing part of my friend*s brain did certainly tell 
him the truth. He knew that there was no heel there. 
Nevertheless, even that knowledge could not change 
the reports which faithful fibers were bound to send to 
headquarters in the brain. Something was out of order 
in their neighborhood, and they clamored for help until 
it came in the shape of a hot-water bag. 

Structure of the Neuron. From all this it is evident 
that nerves, brain, and muscles are pretty closely con- 
nected Indeed, a microscope in the hands of a scien- 
tist reveals strange secrets about this connection and 
about the structure of nerve substance. I shall state 
a few of these hidden truths in a straightforward, matter- 
of-fact way : 

I. Just as muscles are made up of muscle fibers, 

each one of which is a muscle cell, so too is nerve 

substance made up of nerve cells. 


2. A nerve cell is called a neuron. It is made 
up of four parts: cell body, nucleus of the cell, — 
its most essential part, — axon, dendrites. A nerve 
cell has but one axon. It stretches off to a greater 

Four Neurons 

A and C. from (he cerebellum; B, from the spinal cord; D, from the 

cerebrum ; a, the axon. The cells A and D are sulned so that the main 

body and the dendrites are black ; B and C show the nucleus 

distance than the other fibers. It is straighter and 
has branches of its own that extend from it at 
right angles. When a cell body has several project- 
ing fibers it is easy to pick out the axon, because 
the other fibers — the dendrites — are shorter and 



branch out in crooked and forked fashion. The cell 

body part of the neuron is gray, but the fibers that 

stretch away from it 

look white because 

they have a white 


3. Each separate 
fiber in any bundle 
of nerve fibers is 
the long axon arm 
of some neuron. 

4. The cell bod- 
ies of the nervous 
system are located 
in the cortex of the 
brain, in the center 
of the spinal cord, 
and in the ganglia. 

5. A ganglion is 
a group of nerve 
cells unprotected by 
any bony covering. 
There are impor- 
tant ganglia in dif- 
ferent parts of the 
body (see Chapter 

Where the Stimulus goes. Inter- 
twined Neurons in the Cortex 
Notice the countless crooked dendrites and 
the many straight axons which run up and 
down (highly magnified] 
(After KoUilter) 


6. Nerve fibers carry stimuli to the spinal cord. 

There other fibers from other cell bodies receive 

the stimulus and hasten it on to cell bodies in the 

cortex of the brain. These cell bodies then send 

down commands and messages by other sets of 

connected fibers which stretch away to this part 

of the body or that. 

Nerve Telegraph Stations. Wherever cell bodies are 

clustered, whether in brain, spinal cord, or ganglion, 

there we have that interesting place, a nerve telegraph 

station. It resembles a city telegraph station in two 

ways : 

1. It has fibers that do the work of wires and con- 
nect it with different points here and there. These 
carry messages hither and thither. 

2. If a fiber is separated from its own particular 
cell in that central cluster, it is as useless as is 
a telegraph wire after it has been separated from 
its telegraph station. 

We see, then, that the vital part of each nerve cell 
is the gray cell body, and we realize why it is that a 
cluster of hundreds and thousands of these cells becomes 
one of the most fascinating centers of activity in the 
world. Especially so, when it appears that each fiber 
that enters the central station is responsible for one sort 
of message alone, and that, so far as we know, it can 
never carry a message of any other kind. 


Since the two sets of fibers carrying messages in 
opposite directions are so close together, the ignorant 
person might ask whether or not any mistakes are 
ever made in the work they do. The answer is, that 
this never happens. Never in a single instance does 
any fiber in any bundle carry a message the wrong way 
or exchange its message for that which a neighbor fiber is 
carrying. The reason is that each fiber is separated from 
all the others by its own particular outside wrapping. 

What the Gray and White Substances are. And now 
we understand the gray and white substances of the 
brain. The gray is a mass of millions of cell bodies 
packed together and joined to each other by white- 
covered fibers. 

The white stuff is a compact mass of fibers, each 
one of which stretches away in its silvery sheath from 
its individual cell in the gray layer. Millions of these 
fibers join one part of the brain to another part of the 
same brain. Still other millions go downward towards 
the spinal cord, and there, within the firm protection 
of the backbone, stimuli of every sort speed upward 
to the brain, while at the same instant, on other fibers, 
countless commands go from the brain to the muscles 
of the body. It was by studying these commands and 
stimuli that men learned at last what special work is 
always done in special regions of the brain. By the same 
study, also, they learned what fatigue does to nerve cells. 


Fatigue and its Remedy. Several years ago Dr. C. F. 
Hodge studied the brain of the English sparrow and 
learned some astonishing facts about fatigue and rest. 
He made two examinations every day; one in the morn- 
ing, to see how the cells looked after a long night of rest, 
the other in the evening, to see how they looked after 

the day's work was done. 
His great discovery was 
that always the innermost 
center of each cell — the 
nucleus — was plump and 
round and full in the 

A Sparrow whose Brain Cells are morning before WOrk bc- 

GRowiNG Weary with Work g^n, and that it was much 
smaller, much more jagged and irregular, after the day's 
work was over. From his experiments Dr. Hodge de- 
cided that, for all of us who own brain cells, it is the 
cell body and not the fiber of each neuron that gets tired. 
The case for one and all can be stated in two sentences. 

1. Before exertion the nucleus is large and round, 
smooth and regular. 

2. After prolonged exertion the nucleus is small, 
jagged, and irregular. It has lost substance and 
become crumpled. 

Dr. Hodge also learned that when tired cells have 
a chance to rest, the nucleus grows larger, rounder, and 
more regular again. From these and other experiments 


we learn that when we are tired in body or brain we 
cannot expect satisfactory work from our nerve cells, 
and that we should not overtax them when already tired. 
This does not mean that vigorous exercise does us harm. 
On the contrary, it is absolutely necessary to us. The 
one point to remember is that we must always balance 
exercise by rest. The man, woman, or child who gets 
up tired in the morning is losing the balance between 
work and rest. He is getting too little sleep to offset 
his fatigue. If he wishes to do good work, he must rise 
in the morning with the feeling of being rested. By this 
feeling he will know that his nerve cells are in prime 
condition, ready to serve him well. 


1. Mention ways in which sensations help us. 2. What does the 
microscope show about the nerves ? 3. Describe the work of different 
sets of fibers when a baby sees a flame and puts his finger into it. 
4. What does the brain do when the stimuli reach it? 5. Which are 
the longest fibers ? 6. Describe the distribution of the nerves. 7. Where 
do we find great clusters of nerves ? 

8. Describe the dog that had lost the use of the cerebrum. 9. What 
of man when he loses his cerebrum? 10. What mental activities are 
connected with the cerebrum? 11. Where is the cerebrum located? 
12. Describe the appearance of a brain preserved in alcohol. 13. Where 
are the parts held together? 14. Give the names of two important divi- 
sions of the brain. 15. Name the larger and describe it. 16. Where is 
the cerebellum ? 17. What can you say about brain convolutions ? about 
the thickness of the gray layer ? about its use? 18. What about injury to 


special parts of it ? 19. Describe the centers in the cerebrum. 20. What 
is the cortex? 21. Tell how important it is, and how it is protected. 
22. What separates the brain from the skull? 

23. What is the difference between large nerves and small nerves? 
24. Where are the largest nerves found ? 26. Describe the backbone 
and the nerves that pass through it 26. How many fibers may be in 
each nerve? 27. How do fibers pass from one bundle to another? 
28. Is there danger of their losing their way? 29. What points do 
fibers connect? 30. When do fibers become useless? 31. WTiat would 
have happened to the baby who burned its fingers if certain sets of nerve 
fiber had been cut across ? 32. Let six pupils give six facts about the 
neuron. 33. In what two ways is a cluster of cell bodies — a ganglion 
— like a telegraph station ? 34. What is the essential part of a nerve 
cell? 36. How often do fibers make mistakes? 36. How often do 
they exchange messages ? 37. What is the gray layer of the brain ? the 
white part of the brain? 38. Describe a tired nerve cell 39. What 
is the point to remember about fatigue and rest? 



The Work of the Cerebellum. A French scientist named 
Flourens once noticed that although a pigeon with a 
useless cerebellum does not seem to suffer, it does, never- 
theless, have the greatest difficulty in standing and in 
moving about. He saw that when it moves, the muscles 
do not pull together in orderly fashion, but rather in an 
independent, helter-skelter way, — each muscle, as it were, 
pulling for itself without reference to any other muscle, 
so that instead of walking, the poor bird turns one 
somersault after another in rapid succession. 

Dr. Flourens also noticed that the less the cerebellum 
is injured, the less the pigeon is troubled with these dis- 
orderly movements, although even then it walks in a 
staggering, drunken way. 

From these and other facts which they have gathered, 

men who study the subject conclude that the cerebellum 

is an enormous help to the cerebrum in the matter of 

controlling such muscles as are guided by our will power. 

They say that while the cerebrum is the commanding 

general of the nervous system, the cerebellum is the 



chief of stafif, the one that helps take charge of num- 
berless movements which we have learned to make 
through persistent, diligent practice. When we were 
babies and were learning to walk, we thought about each 
step as we took it If our minds were diverted, if certain 
special neurons 
stopped attending 
to our footsteps, we 
tumbled down in- 
stantly. For weeks, 
and even months, 
we hardly dared to 
walk alone. 

To-day, however, 
after years of prac- 
tice, we walk 
anywhere without 
giving a thought 
to any separate 
footstep. We even 
step so fast that 
we run and dance; we ride the bicycle, and we swim. 
Indeed we do all this so well, and we are able to think 
of so many other things while we use our feet and hands, 
that it looks very much as if they had become quite in- 
dependent of the brain. This, in fact, explains the whole 
situation. Their movements have at last been put in 

(After Ramon 7 Cajal) 


charge of a different set of nerve cells. The happy part 
of this arrangement is that the particular neurons which 
do what we might call this underground managing for us 
are, as a rule, more trustworthy than those which help 
our conscious thinking and moving. 

Training the Neurons. The same law and the same 
power of the neurons hold good in other directions also. 
What trained baseball player stops to think of each sepa- 
rate run and slide, how to hold the bat, how to pitch the 
curved ball, how to catch it? He simply takes his place 
to play the game ; he trusts his trained neurons to help 
him, and he finds that almost unconsciously he makes 
the right motion at the right instant, that he plays 
the game even better than he. could tell another how to 
play it. 

This is quite as true in still other kinds of action. I 
know a freshman in college who has lately taken up a 
noticeable practice. Often when he stands still, and 
even while he walks, he may be seen suddenly to 
straighten his neck and press the back of it firmly 
against the inside of his collar. Why does he do it? 
Simply because he believes that his head bends too 
far forward to be creditable, and he has made up his 
mind to put his neck muscles in charge of a. new set 
of neurons. Whenever he thinks about it, therefore, 
he sends imperative orders to those muscles. They 
straighten his neck promptly, and he gets his head up 


where it belongs. He knows that each pull in the right 
direction helps, and that if he persists long enough he 
will finally get his neurons so well trained that they will 
end by making the muscles hold his head up all the 
time without any conscious thought about it on his 
own part, and that this will relieve his mind for other 

Results of Training the Neurons. When we are teach- 
ing ourselves new lessons, the time for encouragement 
is at the first sign that we are doing the desired thing 
unconsciously. For example, we may be training various 
sets of nerve cells to help us do certain things in defi- 
nite ways, — to walk like a soldier, to sit erect, to talk 
in a low voice, to hold knife and fork and spoon as we 
should, to recite the multiplication table, or to repeat 
a poem, — and day after day we may be discouraged 
by the fact that as soon as our own thought is off the 
subject we fail in our struggle; but, without warning, 
some day the moment for encouragement will come. 
We shall find that we have done the desired thing as 
we wished to do it, even while we were not thinking 
about it, and by that sign we shall know that we have 
reached the turning point. By being persistent a little 
longer, those particular neurons will have their lesson 
by heart, the fight will be won. 

This method of training is admirable for any neurons 
which we wish to press into service, but, even when we 


are not training them on purpose, they often get trained 
in spite of our real desire. As an example, think of those 
which control the muscles of the face. When you are 
glad or sad some day, try to catch the expression of 
your face in the mirror, or look at the face of some 
one else who is happy, or angry, or suffering great pain. 
In every such case you will find that, unconsciously, the 
muscles tell a plain, straightforward story. 

Neurons and Facial Expression. . The truth of course 
is that almost every feeling we have may express itself 
in the face, and that each repetition of the expression is 
one more lesson for the nerve cells that control those 
muscles to learn. The sad man, the worried man, the 
happy man, the hopeful or the discouraged man — each 
has his own telltale face muscles, and a good student of 
human nature learns to read these faces almost as easily 
as if they were the pages of a book spread out before 
him. It is evident, then, that every young face is shap- 
ing itself to the expression it will have later, and that 
the time is sure to come when the tale of our inner 
lives will be told by the outward expression of face and 
manner. When this time arrives we may long to hide 
the facts about the history of our emotions. But we 
shall find that we cannot cheat the neurons. Instead, 
the story which they have been trained to tell will 
proclaim the facts about us whenever and wherever 
we show ourselves. 


Four Great Truths about Neurons. Thus far in this 
chapter we have laid bare four great facts: 

1. He who wishes to learn to do any sort of 
muscular work easily and well, and to make sure 
that what he has learned cannot be forgotten, must 
by diligent practice put the performance of that 
special work in charge of its own set of unconscious 

2. Neurons are often so quick and clever that 
they learn that which we would much rather they 
would not learn, and they proclaim the truth even 
when we wish them to hide it. 

3. If we wish our neurons to declare that we 
are courageous, kind, and sincere, the only way to 
make them do it is by being courageous, kind, and 

4. He who pretends to have desirable qualities 
when he really lacks them will find that through 
the power of his neurons, in spite of his desire, 
he actually declares to those whom he meets 
that it is all mere pretense. 

In addition to all else, our special-sense neurons 
need training. They are located in the cortex, and 
they control seeing, hearing, touch, taste, and smell. 

Training the Senses. A friend of mine whose senses 
are all in good working order is developing two of 
them in a delightful way. He thinks he is simply 


studying birds. This indeed he does, but while he 
studies birds his eyesight grows keener in its power 
to recognize them, while his hearing also grows more 
trustworthy; and the outcome of it is that almost 
never does a bird fly overhead within sight or sound 
of him but he recognizes it at once. 

Sometimes he knows it by the way it flies; some- 
times by the color of wing, breast, or tail; sometimes 
by its shape; sometimes by its size; sometimes by 
its song. Whatever the mark, in a flash, when he 
sees the bird or hears it, he knows it and names it. 
Others who are with him may have seen nothing but 
a bit of color passing by or a small shape on a sway- 
ing tree top; but he has seen and heard all that the 
trained eye and ear can see and hear, and he is able 
to give to the color, the shape, or the sound its own 
definite bird name. 

Whether a man watches birds or collects stamps, 
coins, or pictures, — whether he is blacksmith, preacher, 
carpenter, lawyer, merchant, editor, sailor, or newsboy, 
— he will find that trained senses lead to the promised 
land of success. 

Men in all countries have discovered this for them- 
selves. We are told ^ that natives in central Australia 
know every bird track and every beast track by sight, 
and that this knowledge does not come to them 

1 Related by Baldwin Spencer and F. C. Gillen. 


through any accident It seems, indeed, that from 
earliest childhood Australian boys and girls are taught 
to notice tracks of all sorts, and that at the same 
time they are also taught to imitate these tracks with 
their fingers in the sand. 

The result is that a full-grown, experienced tracker, 
as he is called, can follow obscure tracks which we 
should never notice and can recognize them even as 
he rides past rather swiftly on the back of a horse. 

But eyesight and touch do not stand alone ; the power 
to smell may be trained, too. Think of the Indians in 
Peru. Dr. Carpenter says that in the darkest night 
these people can tell, by the smell which reaches them, 
whether a stranger who approaches is an Indian, a 
European, or a negro. For them, as for the others, it 
is a trained sense that does the work. 

We see, then, that the same law is true for all sorts 
of people, in lands however far apart Everywhere, he 
who wishes the keenest and the surest sense of sight or 
sound, taste or smell or touch, may secure it by close 
attention and constant practice. In other words, by atten- 
tion and diligent practice we may form right habits for 
our senses and develop the power which we desire. 

The encouragement is that by being persistent enough 
in the direction of the senses — or in any other direction 
— we compel the nervous system to help us form habits 
that will stand by us for life. 


Machinery of the Senses. Along with all these facts 
it is important to remember that each separate sense 
depends on the work done by three parts of a delicate 
piece of machinery. 

1. Apparatus in which nerve endings receive the 
stimulus — eye, ear, nose, skin, etc. 

2. Fibers which carry the stimulus. 

3. Cell bodies in the cortex — the gray covering 
of the brain — which recognize the stimulus. 

The Brain the Center of the Senses. In the case of 
each sense, also, we must suppose that the outside ap- 
paratus itself knows no more about what is happening 
to it than the mouthpiece of a telephone knows what 
we say when we speak into it. In point of fact the re- 
ceiving apparatus of each sense is nothing more than a 
marvelous device for receiving its own special kind of 
stimulus. Eye, ear, skin, nose, tongue — each is a piece 
of apparatus fitted with nerve-endings that receive stim- 
uli of a certain kind and send them to the brain on a 
distinct set of fibers. The cell bodies in the brain feel 
our sensations for us. 

Since we know that exercise develops any part of the 
body, and since we have learned that our senses may be 
developed by habits of attention and by constant prac- 
tice, we are not surprised to hear that by examining a 
brain after death a trained scientist can tell just which 
set of nerve cells did the most work during life. 


Enlargement of Sense Centers. These men may, for 
example, take a bird that has lost its life and point to 
a certain place on the cortex, " You see it is very much 
enlarged," they say. " That is the part that always had 
the most exercise. It is the sight center of the brain." 
And at once we call to mind the stories we have heard 
about carrier pigeons — about the keenness of their 
vision and the distance they fly to reach home again. 

The brain of a dog may be examined next. " There ! " 
the scientist exclaims, "do you see this part? It is the 
center for smell, and it is always greatly enlarged in 
dogs." And now we recall all our dog stories. We re- 
member that a bloodhound will trace a man through a 
crowded city, that the scent of a dog is one of his most 
remarkable points. 

The examination might go on from animal to animal, 
each brain showing that one of the senses was more 
highly developed than the others. 

The Sense Centers of Laura Bridgman. Human brains 
are better balanced, unless something has gone wrong. 
This was true of Laura Bridgman. She was deaf and 
dumb and blind and had no sense of smell. Her one 
connection with the world was through her sense of 
touch. As a result, the cell bodies of touch received 
constant daily exercise, while the nerve cells of all the 
other senses received no exercise whatever. Then came 
the startling discovery; for after Laura Bridgman died 


her brain itself told the story of her senses. Doctors 
examined the cortex and found that it was thinnest 
at the centers of seeing, hearing, tasting, and smelling. 
More than this, as might have been expected, the doc- 
tors also found that the touch region of Laura's brain 
was wonderfully developed. In view of all this we draw 
the following conclusions for immediate use: 

1. Although the apparatus itself does nothing 
but receive stimuli of one sort or another, still, if 
it is ruined by disease, accident, or careless use, no 
amount of striving on our part will restore it to us. 

2. If the apparatus of one sense has been wrecked, 
the other senses may be so highly developed as to 
help make up the loss. 

3. Persistent exercise of any sense will increase 
the thickness of the part of the cortex to which it 

Although no examination of the cortex of our own 
cerebrum is possible while we are alive, still we may 
have the comfort of knowing that we are improving its 
quality here or there in proportion as we are giving one 
sense or another more or less exercise. The truth is that 
our senses are our best friends or our worst enemies in 
just such measure as we train or neglect them. 

By the foregoing facts we have learned that five 
special senses are the avenues that lead up to the 
mind. The following additional facts are valuable. 


Structure of the Eye. Here we have a socket of bone 
lined with a cushion of fat. Within this socket is the 
eyeball. To protect it are eyelid, eyelashes, and the 
eyebrow. Six small muscles move the eyeball about. 
One end of each is fastened to the eyeball, the other 
end to the inside of the socket itself. The lachrymal 

TKE Retina 

s; /, lens; ?>, vitreous 

gland, within the socket, manufactures moisture con- 
stantly. This moistens the eyeball, then runs off through 
two small canals, one from the inside corner of each eye- 
lid. From these canals tears run into the nasal duct and 
then into the nose. If the lachrymal glands manufacture 
moisture very fast, the eyes overflow, tears stream down 
the cheeks, and we say the person is crying. We mean 
that the duct cannot carry the liquid off fast enough. 


The eyeball is made up of three layers : the sclerotic 
coat outside, the choroid coat, and the retina inside. 
The sclerotic coat is really the white of the eye. In 
front it is joined to the cornea. This is transparent, like 
a window, and through it light goes into the eye. Back 
of the cornea lies the iris, a circular curtain of muscle, 
lined with coloring matter and pierced by a round open- 
ing called the pupil, through which light enters. The 
size of this opening is controlled by muscles which make 
it smaller in bright light and larger in dim light. This 
iris curtain is the colored part of the eye. What is the 
color of your iris? The crystalline lens is back of the 
iris. It focuses the light on the retina. It also divides 
the inside of the eyeball into two compartments. The 
small one in front, just behind the cornea and divided 
in two by the iris, is filled with a watery substance, the 
aqueous humor, that runs out if the eyeball is cut into. 
The large compartment back of the lens is filled by a 
transparent jellylike substance inclosed in a membrane 
and called the vitreous humor. Behind all this is the 
lining of the back of the eye — the retina. 

The optic nerve enters the eye from the cerebrum and 
spreads itself out on the retina. Light rays enter through 
the pupil in the cornea, pass through the crystalline lens, 
strike on the retina, and make an image there. By the 
help of the optic nerve the seeing center of the brain 
receives the picture in a flash. The whole structure is 


a marvelous camera, more delicate than any man-made 
device. We need to treat it with the greatest care. The 
following directions are important : 

Treatment of Eyes; Headache, Eyestrain, etc. In strong 
light, lower the eyelids. Sit erect while reading. Have a 
good light on any close eye work — reading, embroidery, 
drawing, and the like. Light should shine upon the 
work from the left. It should not shine into the eyes. 
Avoid twilight reading. Do most of your eye work by 
daylight, not by artificial light. Eyes are strained by 
light that flickers or is dim. Any strain damages the 
eyesight. Hold your book about eighteen inches from 
the eyes. If you cannot do this without eyestrain, if you 
have frequent headache and no auto-intoxication, your 
eyes should be examined. You may be nearsighted, 
and have to hold your work too near to the eyes. You 
may be farsighted or even slightly cross-eyed. You may 
have what is known as astigmatism. In any case of 
strain, see the oculist. He will give you glasses that will 
correct the trouble. Spectacles are always better than 
eyeglasses, because they are steadier on the nose. They 
strain the eyes less. Whether you wear glasses or not, 
in any close eye work look up frequently to rest the eyes. 
Remember that you have but one pair to serve you 
through life, and that the better you treat them the 
longer they will last. Use your eyes very carefully after 
measles, scarlet fever, chicken pox, diphtheria, and any 


disease that weakens the system. Never wipe the eyes 
on a public towel. Disease microbes may be on it. Keep 
your own fingers from your eyes for the same reason. 

Structure of the Ear. The outer ear includes all we 
see of it, and also the auditory canal into which sound 

A Cut 
a, the lube; #, the eardrum; 

waves go. At the inside end of this canal is the mem- 
brane called the eardrum. It is stretched across the 
canal, and sound waves that strike against it make it 
vibrate. A blow on the ear often breaks it On the 


sides of the canal are small glands which secrete wax, 
a protection to the drum. The middle ear is just be- 
yond the drum. In it are three tiny bones, called ham- 
mer, anvil, and stirrup. Ligaments of the smallest size 
hold the bones together in a chain and fasten them to 
the underside of the drum. When sound waves reach 
the drum it vibrates. The small bones are slightly 
moved by this vibration and pass it on to the cochlea 
at the entrance of the inner ear. This cochlea is an 
intricate structure shaped like a shell. Within the inner 
ear are bony spaces and tubes, called the bony laby- 
rinth. Inside the bony labyrinth is the membranous 
labyrinth. And here it is that we find the ends of the 
fibers of the nerve of hearing — the auditory nerve. 

These nerve endings receive vibrations of sound. 
The vibrations travel to the brain on the auditory nerve. 
It is in the brain that we do our hearing. The en- 
tire ear with its three parts — outer, middle, and inner 
— is merely a combination that forms the road by 
which sound waves must travel to reach the special 
hearing center of the brain. The eustachian tube is a 
narrow connecting passage between the middle ear 
and the pharynx. 

Hygiene of the Ear. Three things must be done for 
the health of the ear: 

I. Keep the auditory canal clean, that wax may 
not accumulate in it. 


2. Don't catch cold. This often inflames the 
eustachian tube and other membranes, giving in- 
tense earaches. 

3. Never box the ear. The sudden crowding of 
air against the eardrum may split it. 

The Sense of Smell. Smell stimuli are received by 
olfactory cells spread out on the sensitive lining of the 
nose. Nerve fibers go from these cells up to the brain, 
and there it is, in one definite locality, that we do 
our smelling. The olfactory nerve is simply the road 

The Sense of Taste. Nerve endings on the tongue are 
called " buds of taste." Each is joined to the brain by 
many nerve fibers, and these transmit taste stimuli to 
the brain. It is in the taste center of the brain that 
we do our tasting. 

The Sense of Touch. By means of this fifth sense, 
endless information reaches the brain from the surface 
of the body. The nerve endings themselves are in the 
skin. Longer and shorter nerve fibers carry touch mes- 
sages to the brain, and there we do our feeling. 


1. Describe Flourens' work with pigeons. 2. How does the cere- 
bellum relieve the cerebrum ? 3. Describe learning to walk. 4. Men- 
tion other activities that end by being done unconsciously. 5. Describe 
training the neurons. 6. What are the result^? 7. What causes a 


person's facial expression? 8. Describe some case in which nerve 
cells are trained in spite of our real desire. 9. Give the four great 
laws of nerve cells. 10. In studying birds, what special senses 
are trained.^ 11. How do native Australians train their eyesight? 
12. In training the senses, what is the secret of success? 13. What 
three parts are there to the machinery of each separate sense? 
14. Where is the center of the senses? 15. What can you say about 
the enlargement of sense centers ? 16. Which sense is most developed 
in a bird? in a dog? 17. Tell about Laura Bridgman, and about her 
brain after death. 18. What three lessons do we learn from studying 
the senses? 19. How many special senses have we? 

20. Describe the location of the eyeball ; its protections ; the muscles 
that move it. 21. What does crying show about lachrymal glands? 
22. Name the layers of the eyeball. 23. Why is the cornea like a 
window? 24. Where and what is the iris? the pupil? 26. What makes 
the pupil grow larger or smaller ? 26. Where is the crystalline lens ? 
27. What does it do? 28. What is the aqueous humor? the vitreous 
humor? 29. Where does the optic nerve spread out? 30. Mention 
different parts of the eye through which light passes to get to the 
retina. 31. Where is the picture formed which we see? 32. Where 
do we really do our seeing ? 

33. What is the outer ear? 34. Where is the eardrum? 35. What 
makes it vibrate? 36. Where does earwax come from? 37. Describe 
the middle ear and its bones. 38. How do sound waves reach the 
cochlea ? 39. Describe the cochlea ; the bony labyrinth ; the mem- 
branous labyrinth. 40. What is the auditory nerve? 41. Where do 
we do our hearing? 42. What is the one thing that the entire ear 
is made for? 

43. Name the nerve by means of which we do our smelling. 
44. Where do we really smell, in the nose or in the brain? 45. Where 
are the "buds of taste"? 46. What joins them to the brain ? 47. Where 
do we do our tasting? 48. Where are the endings of the nerves of 
touch? 49. Where is it that we do our feeling of every kind? 




Vital Activities Independent of our Will. Before study- 
ing this chapter, test yourself in two ways: First, try 
with all your might to make your heart stop beating. 
Try to prevent the great arteries from expanding and 
contracting as the blood surges through them in pulses. 
See whether, by thinking and willing hard enough, you 
can prevent your sweat glands and oil glands from 
manufacturing salt water and oil. Will your stomach 
obey you when you command it to stop digesting your 
food ? 

Now turn the tables. Say to your heart as it pounds 
steadily along : " Beat faster. Beat faster. You must beat 
faster." Will it obey you? No; it goes neither faster 
nor slower by the fraction of a second. Your brain and 
your heart seem to be as independent of each other 
as if they belonged to different bodies and lived in 
different worlds. 

Nevertheless, as we all know, life itself depends on 
the beating of the heart. We know that whenever it 

stops and fails to start again we shall die, but from 



year's end to year's end we think nothing 
about it. At night we lie down to sleep 
with no anxiety lest the steady pulsing 
may cease. By day we run, dance, dive, 
swim, play leapfrog and football, walk on 
our hands and turn somersaults, knowing 
all the while that the heart is affected 
by every move we make; but at the 
same time we seem to know that some- 
how the body has an arrangement for con- 
trolling its most important machinery 
whether we pay attention to it or not. 
Vital Activities Controlled by the Gan- 
glia. Up and down on each side of the 
backbone is a chain of ganglia which 
is more important to life, perhaps, than 
any other part of the nervous system. It 
seems to be nature's device for relieving 
the brain ; a device for keeping the vital 
machinery running by day and by night 
without our needing to think about it. 

This system of nerves is the means by 
which the heart, stomach, and other organs 
which are independent of our conscious "'**^ ordwith 

'^ J Spinal Nerves 

control are able to do tlieir faithful work ontheieftareafew 
whatever commands we give them. It is sympathetic ganglia 

„ , , , . joined by their rope 

caltea the sympathetu nervous system. of nerve fibers 


Strttcture of the Sympathetic Nervous System. So 

far as location and arrangement are concerned, it is 
not very difficult to understand the facts about this 
system, and the following outline will give them as 
simply as possible: 

1. Forty-nine ganglia unite to form the main 
part of the sympathetic nervous system. These 
ganglia belong together as a complete set. Twenty- 
four lie on one side of the backbone, twenty-four 
on the other side, and one lies in front of the 
lowest vertebra. 

2. Each of the forty-nine ganglia is connected 
with its neighbor above and its neighbor below 
by what might be called a rope of fibers. 

3. This string of ganglia, held together by its 
peculiar fiber rope, seems to hang like a loop, with 
the backbone as a pole in its center. 

4. The cell bodies in the different ganglia send 
fibers off to definite parts of the body — to heart, 
stomach, liver, and elsewhere. At these different 
places the fibers are so closely woven together 
that they form a network called a plexus; small 
ganglia are interlaced with each plexus. 

5. One very important plexus is near the heart; 
'another is near the stomach. 

A Nerve Plexus. On the street the other day my 
six-year-old friend suddenly bent his head forward 


and thumped it into the stomach of an elderly man 
who came that way. The boy was surprised when 
the old man bent himself double and almost groaned 
aloud, for the child himself knew nothing about the 
plexus near the stomach, neither did he know that 
wherever fibers are thickest, there it hurts most to 
be punched. The boy's brother, fourteen years old, 
understood the situation perfectly. " Because," as he 
said, " you see it hurts awfully to be thumped in your 
stomach like that." 

But all this has to do with the outside of the 
stomach. Now recall Dr. Cannon's experiments with 
cats. Think of the close connection which he dis- 
covered between the state of the mind and the work 
the stomach is willing to do, and do not forget that 
it is through nerves alone that the mind can ever 
affect the stomach in this way or that. 

Good Temper and Digestion. A friend of mine says 
that many a time when he was young he himself had 
the cat's experience. He was quick-tempered, nervous, 
and excitable, and he found that if he lost his temper 
while he was eating, or if he even became unpleasantly 
excited, he immediately felt as if all the food in his 
stomach had turned itself into a weight of lead that 
could not be dislodged. 

Sometimes his stomach even went so far in its 
rebellion as to force up everything he had swallowed 


Experiences of this sort taught the boy one of the great 
lessons of his life — that he must keep calm and serene 
at mealtime. Later he learned that, in thousands of 
cases, bad digestion comes from a bad disposition, and 
not a bad disposition from bad digestion, as so many 

Why Happiness Helps the Body. From these and 
other observations and experiments scientists find four 
good reasons why happiness helps not only the stomach 
but all other parts of the body too. 

1. A happy state of mind affects the ganglia in 
such a way that they compel the small blood 
vessels to expand. This allows fresh blood to flow 
easily through them. 

2. A happy state of mind affects the nerves that 
control the lungs. They inhale more air. This 
means that they get more oxygen; and this, in 
turn, means that the blood is more completely 
purified in the lungs. 

3. A happy state of mind affects the ganglia that 
control the heart, making it beat faster; this forces 
fresh blood rapidly through the expanded blood 
vessels. And rapidly moving blood gives rich nour- 
ishment to nerve cell and muscle, making it possible 
for them to do good, energetic work. 

4. A happy state of mind affects the ganglia of 
the stomach so promptly that its churning is better 


done; while, at the same time, more gastric juice 
pours in to help digestion along. 

A cheerful schoolroom, lively games, pleasant friends, 
becoming clothes, comfortable travel by land and by 
water — anything that makes us happy without doing 
us harm is a help to the body through the sympa- 
thetic ganglia. 

We now see why it is that we learn our lessons 
faster, recite them better, and are quicker-witted in 
every direction when we are happy than when we are 
unhappy. It is simply because in the former state every 
organ in the body is doing its best work, and because 
the brain gets the benefit of it all through an improved 
blood supply. The serious fact is that the human 
machine is so delicately balanced that when even the 
smallest part of it fails, the whole may hitch and halt. 
Wear out the fire box or the boiler of an engine, and no 
matter how perfect the rest of the machine may be, it 
will run no better than a worn-out affair that is rusted 
in every joint. 

It matters not where the hitch in the human machine 
begins — whether with too much food, too little masti- 
cation, too little exercise, too much worry, excitement, 
anger, fear, or torment of any mental sort ; for wherever 
the start may be, the feelings are sure to be pulled into 
the reckoning erelong, and after that the trouble is 
increased tenfold. 


Service from the Ganglia. It is evident, then, that we 
have within our own reach methods for securing good 
service from our sympathetic ganglia. 

1. To avoid as if it were a poison each thought 
and emotion that saps the vigor of the ganglia 
— hatred, malice, envy, jealousy, anger, despair, 
discouragement, anxiety, worry, fear. 

2. To help the ganglia through love, joy, hope, 
courage, faith, trust, belief in others, belief in our- 
selves, good cheer. 

3. To obey all the laws of health that we know 
anything about. 

It was in studying this last point that Professor 
Kraepelin and others came to their conclusions about 
the effect of alcohol on nerve tissue and efficiency, as 
described in the next chapter. 


1. What control have you over the beating of your heart? over 
your pulsing arteries? 2. If you should command the stomach to 
stop digesting its food contents, what result would there be ? 3. What 
part of the nervous system has charge of internal bodily activities? 
4. How many ganglia are there in the sympathetic nervous system ? 
6. Where do they lie ? 6. How are these ganglia connected with each 
other? 7. Where do the cell bodies of the ganglia send their fibers? 
8. When fibers are very closely woven together in a network, what do 
they form ? 9. When a man is punched in the stomach, which plexus 
of nerves suffers ? 10. How can the mind influence the stomach ? 


11, What was Dr. Cannon's discovery about the state of a cat's 
feelings and the work of a cat's stomach ? 12. What similar discov- 
ery did a man make about his own state of mind and his digestion? 
13. What effect does a happy state of mind have on the blood vessels ? 
on the lungs ? on the heart ? on the stomach ? 14. What can you say 
about anything that makes us happy without doing us harm ? 15. Why 
is it that we do better work both with the mind and with the body when 
we are happy than when we are unhappy? 16. For the sake of the 
S)anpathetic ganglia, which emotions should we shun? 17. Which emo- 
tions will help these ganglia ? 



Tests made with Students. Several years ago Professor 
Kraepelin of the University of Heidelberg, in Germany, 
did some experimenting in connection with the students 
of the place. He was just the one to carry on the experi- 
ments, because he had already made a special study of 
the nervous system, and because in all parts of the world 
scientific men recognize the authority of his name. He 
himself says that he really wished to save a little of 
the reputation of wine and beer, for he saw that science 
was crowding pretty hard against every drink containing 

In experimenting with his students Professor Kraepe- 
lin always gave small doses. He knew, as we do, that 
those who use alcohol frequently in large doses ruin their 
lives hopelessly. Proofs of this are on every side in every 
land. There are, however, thousands of honest people 
who heartily believe that alcohol taken in small doses is 
a help on all sorts of occasions. It was in this direction, 
therefore, that Professor Kraepelin experimented. 

Various university students were eager to know facts, 

willing to be tested, and quite ready to drink or not to 



drink, according as the progress of the investigation 
required. One test had to do with a man's quickness in 
adding up columns of figures for half an hour a day 
during six days. Those being tested without alcohol 
added their figures as rapidly and correctly as they 
could. Then the alcohol period began, and for thirteen 
days the same students used alcohol and continued 
to spend the half hour a day at their addition tables. 
The work went more and more slowly, until the nine- 
teenth day. Alcohol was then dropped. The men con- 
tinued to add, and there was immediate and marked 
improvement in the work they did. This continued until 
the twenty-sixth day, when they returned to alcohol, and 
once again there was a change for the worse. 

Thus the seesaw between alcohol and no alcohol went 
on until no doubt remained. It was clear to all that the 
men always did poorer work during the alcohol period 
and better work when they had no alcohol. 

Tests made with Typesetters. There was also the test 
with the t)^esetters in Heidelberg. Dr. Aschaffenburg 
carried on this set of experiments. Four skilled men 
were chosen. Three were in the habit of using alcohol 
in small amounts, the fourth acknowledged that he took 
too much once in a while, but all were ready to go with- 
out it or to take it, as the tests demanded. Indeed all 
four men were anxious to know whether they could do 
swifter and better work with the alcohol or without it. 


The amount which Dr. Aschaffenburg gave them on 
the days when they took alcohol was one ounce and a 
quarter; that is, the wine which they drank had about 
two and a half tablespoonfuls of alcohol in it. 

The men drank it fifteen minutes before they began 
their typesetting. For fifteen minutes each day they 
worked at full speed. Each did what he could to set 
up as much type as possible; and yet, as shown in the 
illustration on the next page, in every case but one 
alcohol hindered and did not help him. 

But — and here we meet a curious fact — in every case 
the men themselves thought they were doing better and 
swifter work when they used alcohol than when they did 
not use it. Indeed this is the usual belief of all who use 
alcohol. Still, many careful experiments prove that the 
opposite is true. 

Experiments with Soldiers. Sweden has turned special 
attention to her soldiers. She wishes to know whether 
a glass of wine or beer taken before the shooting begins 
will help or hinder a soldier who tries to hit the enemy. 

Lieutenant Rengt Boy carried on the experiments. 
The soldiers selected were picked men, all fine marks- 
men. Their targets were two hundreds yards away, and 
guns and rifles were used. On different days the men, 
in groups of six, were tested with alcohol and without 
it. The amount of alcohol given was about three table- 
spoonfuls. This was taken in the shape of wine or beer, 

^h hoh-alcoual ija.v es^alcohol dai 

The Records of Four, Men 

Each group of four columns shows the work of the same man for 

essive days. Black columns show how many letters they set 

c-alcohol days. Dotted columns show how many letters they 

set up on alcohol days 



sometimes the night before, sometimes within an hour 
of the target practice. The result of it all was the dis- 
covery that in every instance each man in each group 
did his quickest firing and his best hitting when he 
had had no alcohol whatever for two or three days 

Target Practice for Swedish Soldiers 
They need steady nerves 

beforehand, and that he did his poorest work when he 
had used alcohol at any time within twenty-four hours. 
As staff surgeon Memetsch reports: 

When under alcohol the result was 30 per cent less hits in quick 
fire ; and the men always thought they were shooting faster, whilst 
actually they shot much more slowly. When slow aiming was allowed 
the difference even went to 50 per cent. 


Alcohol and the Neuron. With these facts in mind we 
are not surprised to learn that the condition of the neuron 
of the drinker is often quite enough to explain his 

Cells from the Spinal Cord 
The upper cell at (he left is nonnal, with its nucleus in the center. The upper 
cell at the right is dead ; it has no nucleus whatever. The other cells are swollen 
and the nucleus is pushed far to one side. These diseased cells were taken from 
alcohohc persons who died in Claybury Asylum, England. They were drawn by 
Dr. Mott for Sir Victor Horsley 

failures. The illustration tells the whole story. Compare 
that clean-cut, trim, normal cell, taken from a healthy 
brain, with the ruined cells from alcoholic brains. 



1. What tests did Professor Kraepelin of Germany make with 
students ? 2. What do some people believe about the helpful effect of 
wine and beer? 3. Describe the German tests in adding columns of 
figures ? 4. What did these tests prove about the effect of using alco- 
hol when one wishes to do quick, accurate work ? 6. Tell about the 
alcohol tests made with typesetters. 6. How much alcohol did the men 
take on the days when it was given? 7. Describe the experiment 
8. What did the men themselves think about the work they did after 
using alcohol? 9. What did this experiment prove? 10. What did 
Sweden wish to discover about wine and beer? 11. What kind of 
men were selected for the experiment? 12. Describe the experiment 
13. How much alcohol was used? 14. What did the staff surgeon 
say about this experiment? 

15. Describe the appearance of normal, healthy brain cells; of cells 
ruined by alcohol. 16. What sort of work is done by a damaged brain 
cell? 17. Since we cannot see the neurons in a living brain, how can 
we tell what their real condition is ? 



The Public Drinking Cup. On the first of September, 
1909, the Board of Health of the state of Kansas began 
to enforce a new law : 

The use of the common drinking cup on railroad trains, in railroad 
stations, in the public and private schools, and in the state educational 
institutions of the state of Kansas is hereby prohibited, from and after 
September i, 1909. 

No person or corporation in charge or control of any railroad train 
or station, or public or private school, or state educational institution 
shall furnish any drinking cup for public use, and no such person or cor- 
poration shall permit on said railroad train, station, or at said public or 
private school, or state educational institution the common use of the 
drinking cup. 

When this law went into effect, and when thirsty 
people arrived at the station and found that they must 
have their own drinking cups, some of them were dis- 
pleased. They thought the Board of Health was growing 
altogether too particular. But read the following facts 
and judge the case for yourself; I quote the account 
from a report that was printed in February, 1909. 

Professor Davidson of Lafayette College asked ten boys to apply the 
upper lip to pieces of flat, clean glass in the same way as they would 



touch a cup in drinking. These glass slips were then given a thorough 
microscopic examination, and they showed an average of about one hun- 
dred human cells, or bits of skin, and seventy-five thousand bacteria^ to 
each slip. This from one application of the lip. 

A cup which had been used in a high school for several months with- 
out being washed was lined inside with a brownish deposit. Under the 
microscope this proved to be composed of particles of mud, thousands 
of bits of dead skin, and millions of bacteria, among which were scores 
of germs corresponding in all details to those of tuberculosis. Some of 
this sediment was injected under the skin of a healthy guinea pig, and 
in forty hours the animal died. A post-mortem examination revealed 
the fact that death was due to the presence of a sufficient number of 
pneumonia germs to cause blood poisoning. 

A second guinea pig inoculated with the cup sediment developed tuber- 
culosis. Careful inquiry proved that several pupils in the school from 
which the cup was taken were then sufferers from this dread disease. 

Before going on with this chapter, give attention to 
the following statements: 

What a Microbe Is. The word microbe means "small 
life." A microbe is any living plant or animal which is 
too small to be seen without a magnifying glass. Many 
people speak of microbes as germs. This is quite cor- 
rect, for both words refer to the same tiny bits of plant 
and animal life. Most microbes are harmless. Some 
microbes give us disease of one kind or another. These 
are called disease microbes. Each microbe disease is 
caused by its own special kind of microbe. These 
microbes do their mischief after they enter the body. 
Microbe diseases are called preventable, because if we 

^ Different kinds of microbes. 


destroy the microbes, or prevent them from attacking 
us, we are sure to escape the malady. By keeping the 
body in vigorous condition we may avoid illness even 
after certain microbes have attacked us. 

How Microbes Attack the Body. Microbes find entrance 
to the body by one or the other of four different roads. 

1. Through the nose and lungs, in air laden with 
dust mixed with microbes, for example. Any man 
who spits where the saliva may dry and be blown 
about is bringing danger to the air which other 
people must breathe. He who sneezes or coughs 
without a handkerchief held to his face is doing 
the same thing. He is scattering microbes in the 
air, and if he has a cold or tuberculosis, the disease 
microbes are able to give the same cold or con- 
sumption to those who breathe the air after him. 

2. Through the mouth, in food and drink or in 
anything which may be put into the mouth — the 
point of a pencil, a half-eaten apple, an unwashed 
spoon or fork, fingers moistened to turn a page. 
Even a kiss on the lips may be a serious matter. 

3. Through contact with microbes from^ the skin 
of a person just recovering from such diseases as 
smallpox, chicken pox, scarlet fever, and measles. 

4. Through the aid of creatures that puncture the 
skin and leave disease microbes in the blood. Mos- 
quitoes do this, one kind giving us malaria, another 


kind giving us yellow fever. We shall study the 

subject later. Fleas carry bubonic plague from rats 

to human beings. The stable fly carries infantile 

paralysis from person to person. Lice probably 

carry typhus fever. 

Now it is because of such facts as these that we guard 

ourselves from disease microbes at every possible point 

When you next take up a public drinking cup, think of 

the microbes that may be on it When drinking at a 

sanitary fountain the lips touch nothing but water, and 

no harm can be done either to yourself or to those who 

may follow you. The individual drinking cup is equally 


Protection for the Eyes. But the public drinking cup 
is not the only danger that threatens school children. 
Think of pink eye and trachoma, described in Health 
and Safety. They always go by the road of touch. No 
healthy eyes will take either disease unless they are 
touched by something which has already touched dis- 
eased eyes — for example, fingers, a contaminated towel, 
or a handkerchief. 

My next-door neighbor seems to know this already. 
He came from school the other day and said, " Pink eye 
has started in school, but I 'm not going to catch it" 
" How will you escape ? " I asked. " That 's simple 
enough," he answered ; " 1 11 keep my hands away from 
my eyes ; 1 11 never touch them with anything except 


my own towel at home. 1 11 have to do this, because at 
school my hands touch what other boys have touched, 
and I never know what microbes may be on them." I 
commended my neighbor and was glad to see that he 
did save himself from pink eye, although his best friends 
had it. The probability is that they not only touched 
their eyes with their hands but also used the common 
towel. This should be banished from every schoolhouse. 
Even books, used by others, may bring disease microbes 
to us. If possible, avoid books that have become soiled 
through long use. 

So much, then, for the direct ways by which microbes 
may travel from person to person; but what about the 
indirect road? 

Why we Object to Flies. Think of our numberless, 
small, unwelcome neighbors, the flies. Why do intel- 
ligent people object to the presence of flies in kitchen, 
pantry, and dining room ? Why do we carry on an end- 
less fight against them ? For the simple reason that flies 
never either wash or wipe their feet. Yet think for a 
moment where those tiny feet travel. Where dead things 
lie, where filth is worst, where disease has been, there do 
we find flies in greatest numbers. And it is always in 
just such places that they lay their eggs and multiply. 

Study the subject for yourself. Look at the open 
garbage pail in the summer, or at a pile of decaying 
waste anywhere. Notice the multitudes of flies there. 


then notice where flies stand thickest in your home. 
From the barnyard, where they multiply fastest in horse 
manure, or from a sewage farm with feet covered with 
typhoid microbes, they may fly to your dining table and 
leave living microbes on bread, beef, cake, candy — on 
anything you eat For in the line of food, flies enjoy not 
our waste alone but also whatever we have prepared 
with greatest care as food 
for ourselves. They stand 
on this dainty food of ours 
with their soiled feet, and 


The House Fly 
o. egg ; b, larva, or maggot ; e, pupa case, or puparium ; rf, adult male. ( All enlarged) 

we swallow the food plus the microbes which mark their 
footsteps. This danger from the fly is very real. 

Of every hundred soldiers who died in the Spanish- 
American War, twenty were killed by bullets, eighty by 
microbes. And over and over again the doctors blamed 
the feet of the flies for having put typhoid microbes on 
the food the soldiers ate. 


What Flies Eat. But aside from the microbes they 
carry on their feet, there is mischief done by flies 
through the refuse which they are willing to eat. Dr. 
Lord, a scientist, allowed flies to eat sputum from the 
lungs of a man who had tuberculosis. Those flies 

Where Flies Multiply 

then deposited their flyspecks, and fifteen days later 
Dr. Lord examined the specks and found living tubercle 
bacilli in them. Those microbes of tuberculosis had 
been taken into the mouth of the fly, had gone safely 
through its body, were alive when they left the body as 
flyspecks, and after fifteen days were as vigorous as 


ever and ready to threaten the living tissue of human 
beings. Think of the flyspecks which are left on our 
food when flies stand upon it. 

Safety through Carefulness. Such facts as these ex- 
plain the widespread fight against the ever-present fly. 
We have no objection to the little creatures themselves, 
but we greatly object to the diseases which they may in- 
flict upon us. We therefore do what we can to reduce 
their numbers. 

A careful housewife keeps the garbage pail closely 
covered, that flies may not enter and lay their eggs 
there. She has it emptied often and scalded, that such 
eggs as may have been laid on the food before it went 
into the pail may be killed and never allowed to hatch. 
She screens doors and windows and never allows a fly, 
living or dead, to find lodgment on her food, either in 
kitchen, in pantry, or on the dining table. 

A careful grocer meets this same situation in the 
same way. If he must display his foodstuffs to charm 
the passer-by, he puts them under glass or stretches net- 
ting about them. He knows that the sight of flies on his 
foods will drive the careful housewife 'from his door. 

A careful man who keeps horses sees to it that the 
stables are kept clean. He knows that, whenever pos- 
sible, flies lay their eggs in such places; that each egg 
hatches out into a tiny maggot; that maggots soon 
turn into full-fledged flies, ready to lay eggs for another 


generatipn ; and that in our fight against the fly the 
main point is to keep the creatures from multiplying. 

A careful city takes the same facts about flies into 
account. It allows no piles of rubbish to stand about ; it 
allows no dead animals to stay unburied and no stables to 
remain uncleaned. It insists on having clean streets, and 
yards with no neglected refuse in which flies may lay 
their eggs. And it is the desire for health that explains 
this passion for clean things which now moves all civil- 
ized peoples. We wish to breathe clean air in clean 
streets; we wish to eat clean food in which no disease 
microbes may be found ; we wish to be rid of city waste 
promptly because we are not willing to run the risk of 
increasing danger for ourselves from microbes which may 
be in it and which may threaten us later. 

In city and country alike, the intelligence of the citi- 
zens decides what their own life and death prospects 
shall be, for sanitation controls the death rate. 


1. Give what you can of the Kansas law about the common drink- 
ing cup. 2. Describe experiments made with pieces of glass that had 
touched the lips. 3. Describe the appearance of the cup used in the 
high school. 4. Tell about the experiments made on a guinea pig. 
5. What does the word "microbe" mean? 6. Are most microbes 
harmful or harmless? 7. Why are certain microbes called disease 
microbes? 8. Why are microbe diseases called preventable? 9. Why 
should we keep the body in vigorous condition? 


10. By how many roads may microbes enter the body? 11. Give 
several ways by which people can bring danger to the air which other 
people breathe. 12. Mention ways by which microbes may enter the 
mouth. 13. What objection is there to touching the point of a pencil 
to the tongue ? to using unwashed forks and spoons after another per- 
son ? 14. Why not turn a page with a finger moistened at the lips ? 
15. What diseases are contagious through the skin? 16. What small 
creatures give us disease by puncturing the skin and leaving disease 
microbes in the blood? 17. Why have people adopted the sanitary 
drinking fountain ? 18. How does it help ? 19. How may eye trouble 
be passed from person to person? 20. How may one avoid taking a 
contagious eye disease ? 

21. Why do we object to flies? 22. Give reasons why garbage, 
refuse, and decaying waste should never be allowed to accumulate. 
23. Where do flies multiply fastest? 24. What did the doctors say 
about the death of soldiers in the Spanish- American War ? 25. Describe 
Dr. Lord's experiment with flies. 26. What does a careful housekeeper 
do about the garbage pail, etc. ? 27. How does the careful grocer 
guard his foodstuffs ? 28. What does a careful man do about his horses 
and his stables ? 29. What ought he to know about fly eggs and their 
history ? 30. What does a careful city do to protect itself from flies ? 



Country Conditions. If you live in the country, step 
out of doors and see what the sanitary conditions of 
your surroundings are. Examine both the inside and 
the outside of the barn, the stable, the hen yard, the 
outhouse, and the pigpen. Notice the location of the 
well. See if it is near enough to other buildings to 
make it possible for contamination to soak down and 
across until it reaches your drinking-water. Look for 
flies and their breeding places. Decide what ought to 
be done to get rid of them. How about the rubbish 
heaps and the garbage pail? Do you think everything 
is properly clean about the place? 

City Surroundings. If your home is in the city, go 
with some grown friend to the most crowded and un- 
tidy part. Enter any tenement house and make discov- 
eries for yourself. You will find that city crowding often 
reaches a perilous point; that even when people object 
to miserable surroundings, they are sometimes obliged 
to use dark halls, dark cellars, and wretched bath- 
rooms. The real owners of these houses seem to act as 

if they thought the darkness would save their tenants 



from disease as well as from disgrace. Yet in such 
places everything helps disease along. Gas pipes leak 
and sewer pipes are out of order; the air grows heavy 
with carbon dioxide, with illuminating gas, with foul 
gases from broken sewers, with the smell of unwashed 
people and unclean clothes. At the same time damp- 
ness adds to the danger. Even in our day there are 
thousands of people who do not know that dampness, 
darkness, and dirt are just the three conditions that are 
best for microbes and worst for men. 

The Meaning of Sanitation. And it is because all this 
is so true that nowadays we hear so much about sanita- 
tion — the science of securing conditions which favor 
health. The problem itself faces both the country home 
and the city tenement. And in studying it we find that 
always and everywhere we are called upon to guard three 
things in connection with our homes. 

1. The air we breathe. Neighbors cannot allow 
each other to contaminate the air with their disease 
microbes; neither can they permit the presence of 
unpleasant odors from decaying garbage or from 
pigpens, stables, and the like. 

2. The water we drink. This must be so pro- 
tected that even if a neighbor in the country has 
typhoid fever, no waste from his body shall have 
the slightest chance to reach the drinking-water 
of the neighborhood. 


3. The food we eat. This must be fresh and pure, 
without any sign of adulteration. It must be pro- 
tected both by state and national laws and by the 
cooperation of all those who sell foodstuffs to each 
Cleanliness the Watchword. At the present time cleanli- 
ness is indeed the watchword for every community — 
clean air, clean water, clean food, clean surroundings of 
every sort. But it sometimes seems as if people in the 
country had to work harder to gain this cleanliness than 
those in the city. Note the following contrasts: 

1. In the country each home must get rid of its 
own garbage, parings, fruit skins, table waste, bones, 
etc. All this must be carried to the pigs, or it must 
be deeply buried and covered lest it give off an odor 
as it decays. In the city all such waste goes into 
a garbage can, and a man from the health depart- 
ment takes it away. We have no further thought 
about it except to keep the pail scalded and covered. 

2. In the country the kitchen may lack a sink, 
in which case waste water must be carried out and 
thrown in a sunshiny place, that it may not become 
a gathering place for flies. The outhouse must be 
strictly guarded from flies and kept in a sanitary 
condition by the use of lime. In the city the 
waste from every sink and bathroom is carried 
out of town by the sewage system. 


3. In the country such dry wastes as ashes, 
paper, scraps of iron, old shoes, rags, etc. must be 
disposed of by each owner as best he can. Some- 
times part of this rubbish is burned, part buried. 
In the city all such rubbish is packed into bags, 
and at stated times these bags are carried off 
and disposed of by the workers of the city health 

4. In the country the roads often suffer sad 
neglect. In the city, men of the street-cleaning 
department do the work and are paid for it by 
the taxes of the citizens. In fact, all city work of 
every department is paid for by these taxes. 

5. In the country, as a rule, each separate home 
is responsible for the kind of water the family must 
drink, for the well is in a place selected by the 
owner of the house. In the city, water comes in 
pipes from out of town, and the Board of Health 
decides whether or not this supply is safe from 
typhoid-fever microbes. 

From these contrasts it looks as if country folk had 
a hard time and city folk an easy time with their sanita- 
tion problems. But turn to another side of the same 

Sunshine and Air in Country and City. Remember that 
every living creature should be surrounded by sunshine 
and fresh air every day. Then think of the glorious 


chance for both in the country, and of the poor chance 
for either that thousands upon thousands of city people 
have. Think of the towering tenement houses, where the 
streets between are like deep narrow valleys, and where 
children play every day without a ray of sunshine about 
them. Think of the thousands upon thousands of inside 

A Village Home 

rooms in every crowded city, where no outside window 
ever lets in air and sunshine. In 191 1 there were 90,000 
such rooms in New York City alone. Think of persons 
ill in such places. Think of the dark corners and the 
filthy cellars and of the disease microbes safely lodged 
and living in them. Think of all the babies that are here 
robbed of every chance of life and of the little children 
who must surely suffer when an epidemic comes. 


In London the crowding is so great that 300,000 of 
its citizens live in tenements of one room for a family. 
Forty thousand of these live 5 in a single room, while 
8000 live 8 in a room. Other cities are crowded, too. 

Homes in New Vork Cmr 

Rear Tenements and the Death Rate. In New York 
City the darkest and most unwholesome houses are 
rear tenements. These stand so close behind the front 
tenements that the distance between them is from two 
inches to five feet Of course each building keeps 
daylight from the other, but at the same time the rear 


tenement is always the older, the more unclean, and the 
more neglected of the two. Mr. R. W. De Forest tells 
us that at one time, in these rear tenements, one baby 
died for every five that were born. These places were 
then called "infant slaughter houses," because of the 
terrible conditions which killed the children. 

New Tenement Regulations. But, in course of time, 
reform came. A new tenement-house department was 
established, and it made better building regulations. 
The new requirements, condensed here, are worth keep- 
ing in mind as a guide for the building of any home. 

No room without a window opening out of doors; good light and 
ventilation; halls square, broad, light; stairs neither steep nor dark; 
every one of them fireproof ; separate bathroom arrangements for each 
family ; courtyard not less than twelve and a half feet wide and twenty- 
eight feet long ; light everywhere, so that dust and rubbish show plainly 
and microbes have little chance. 

Parks, Playgrounds, etc. Every important city in 
the land is bending its energies in the direction of 
sanitary surroundings for all the citizens. Such sur- 
roundings require clean streets and sidewalks, and the 
prohibition of spitting; houses with modern plumbing, 
and with an abundant supply of sunlight and air; pro- 
tection from microbe diseases; parks and playgrounds 
where children may exercise in fresh air and sun- 
shine; public baths where, at little cost, citizens may 
refresh themselves through cleanliness; water from 


sources uncontaminated by human wastes; food which 
must come up to a fixed standard of purity and be passed 
upon by city inspectors; pure milk from tested cows. 
In most cities the board of health tries to give to its 
citizens all these good things, and it is for us to find out 

Swimming Pool, New Curtis Hall Building, Jauaica Plain (Mass.) 
Indoors the year round 

what is being done by our own board of health for 
the protection of ourselves and our neighbors. 

The Sewage System. Even go as far as to find out 
about the sewage system of your town. Learn how the 
sewage is gathered, where it is deposited, and find out 


whether there is any risk of spoiHng the water or the air 
for other people. Remember that flies go where filth 
is found, and that if sewage leaks, flies will discover it 
and will bring disease germs from it into your home. 
Careful disposal of town and city sewage is one of 
the most important of sanitation duties. And what of 
sanitation and our food supply? Here country and 
city alike are helped by our national pure-food laws. 

Pure-Food Laws and Food Inspection. In 1906 the gov- 
ernment of the United States passed what are known 
as the pure-food laws. Even before this, however, many 
cities had their food inspectors, who hunted out and 
destroyed unfit food. Not so very long ago the food 
inspectors of Cleveland, Ohio, sent 2500 pounds of un- 
fit meat from the market to the garbage plant. Later 
the health officers of the same city seized 38 cattle, 
29 hogs, 4 sheep, and 5 calves, telling the owners that 
the animals were diseased and not fit to be sold for food. 
In 1907 the inspectors in New York City discovered 
and destroyed 362,795 pounds of groceries and canned 
goods which were unfit for use. So the experiences of 
different cities might be multiplied. 

Danger from Dyes. One inspector writes : " I have 
seen candy samples brought to the laboratories and 
boiled down; then rags were dipped in the stuff, and 
after the rags were dried no amount of washing would 
remove the dye." Dr. Kellogg says that "a single glass 


of raspberry soda such as is found at soda fountains was 
found to contain sufficient coal-tar dye to color two 
yards of woolen cloth." Now the objection to these coal- 
tar dyes is that some of them are harmful. It is best, 
therefore, to omit them from our fruit, our candies, and 
our bright-colored drinks. If you feel suspicious of any 
special bright-colored canned fruit, test the liquid for 
yourself. Dip a bit of clean white cloth into it and let 
it dry. If the color will not wash out, you should report 
to a food inspector. He will follow the matter up and 
decide whether or not the color is due to the fruit itself 
or to a dye. 

Canned Food. Food canned in tin should never be left 
in the can after it is opened. Canned meat should be 
used the day it is opened, because it decays soon. Our 
food supply is really safer than it has been for years, 
because food inspectors are on the watch. There is a 
standard set by law for every article of food we use 
— for flour, sugar, tea, coffee, canned meats, canned 
vegetables, canned fruit, honey, molasses, butter, maple 
sirup, and all the rest. And the duty of the inspector 
is to see that what is sold corresponds with what the law 
requires. Many meat markets, fish markets, bakeries, 
and groceries that were careless before are now required 
to be clean and to keep the food they sell safe from flies, 
dust, and soiled hands. In some places hands are not 
allowed to touch bread after it is baked. The pure-food 


law also requires that the label on medicines, sauces, 
catchups, and preserved fruits or vegetables shall declare 
exactly what ingredients are in them. 

Patent Medicines. At the great exposition in San 
Francisco, in 191 5, the American Medical Association 
had a special exhibition to show how much alcohol 
there is in different kinds of patent medicine. It was a 
sorry sight. For by its exhibition the Medical Associa- 
tion showed that almost all patent medicines are worse 
than useless, and that he who buys and uses them runs 
the risk of injuring his health seriously. 

No disease of man causes more despair in our towns 
and cities than tuberculosis. We therefore turn now to 
study its cause and the way to prevent it. 


I. What should be the condition of bam, stable, hen yard, and other 
outbuildings in the country ? 2. Where should the well be placed ? 
3. How about cleanliness in the city ? 4. Visit some crowded part of 
it and describe what you find. 5. What about tall tenements, dark halls, 
unpleasant odors, leaking gas pipes, broken sewers? 6. What three 
conditions are best for microbes and worst for men? 7. What three 
things must people guard in connection with their homes? 8. How 
may the air be kept pure? 9. Why should water be kept pure? 
10. What is the modem watchword for every community? 

II. What do people do with their garbage in the country? in the 
city? 12. What do people do about their sewage in the country? in 
the city? 13. What do people do with their dry wastes — their rubbish 
— in the country? in the city? 14. What about street cleaning in 


country and city? 15. Who is responsible for a man's drinking-water 
in the country ? in the city ? 16. In these five sets of contrasts, who 
seem to have the easiest task in keeping their surroundings sanitary, 
people in the country or people in the city? 17. What can you say 
about the need of sunshine and fresh air for everybody ? 18. What 
chance for this is there in the country ? in the city ? 19. Why are some 
city streets like narrow, sunless valleys? 20. How much sunshine do 
children get who play in the streets of -certain cities? 21. What are 
rear tenements ? 22. Describe the requirements of the new law for 
tenement houses. 

23. When we speak of sanitary surroundings for citizens, what do 
we mean ? 24. What power has the board of health in most cities ? 
26. What good conditions and what bad conditions are to be found 
in your own town? 26. Tell what you can about pure-food laws and 
food inspection. 27. What can be said about the use of coal-tar dyes 
in foods? 28. What articles of food have a standard quality set for 
them by law ? 29. How safe are patent medicines ? 



Ravages of Tuberculosis. Perhaps no discovery con- 
nected with the lungs has ever interested the thinking 
people of the world quite so much as that of Dr. Robert 
Koch in 1882. This man was a German scientist, and 
when he declared that he had found 
the microbe which kills more human 
beings each year than any other one 
disease, the news seemed almost too 
good to be true. 

The fact is that, until 1882, no one 

knew the cause of tuberculosis, or how 

to prevent it. Yet, in all lands, doctors 

have been and still are appalled at the 

death rate that follows wherever the disease goes. By 

studying the records they see that, each year, in New 

York City alone, 10,000 men, women, and children die 

of tuberculosis; that, in the United States as a whole, 

500,000 people are constantly ill with it; that 150,000 

of this number die each year of tuberculosis; and that 

in the world at large, there is about the same death rate 

from the same disease. Moreover, it is evident that 


Tubercle Bacilli 

Three thousand put end 

to end will measure one 



the ranks are quickly refilled by those who were well, 
but who in some mysterious way have been stricken 
with the disease. Doctors also realize that in the whole 
world about 1,000,000 people are killed by tubercle bacilli 
each year. 

Dr. Koch's Discovery. In the past the saddest part of 
the situation was that when a person found he had 
tuberculosis he felt helpless about it. He thought the 
chances were all against his getting well again. He 
even thought there was little to do but to get ready to 
die. Imagine then the great hope that sprang up every- 
where when Dr. Koch announced that he knew where 
tuberculosis came from and how men might escape it. 
He said he had made the discovery by the use of his 
microscope, and that what he found was a living and 
growing thing. He gave the microbe a name — tubercle 
bacillus; studied its size and shape; noticed its habits; 
watched it multiply; learned how it may be conquered 
in the human body and also saw what conditions favor 
its rapid growth. Knowing as he did that each one of 
his discoveries would help save the lives of men, he pub- 
lished his conclusions promptly. Here are a few of his 
facts stated in close succession. 

1. Each separate bacillus is a separate plant. 

2. Each is small and slender like a tiny rod. 

3. Three thousand of these microbes put end 
to end will measure one inch. 


4. Each multiplies by dividing. 

5. The only place where they can multiply is 
in the bodies of men and animals, or in laboratories 
where scientists raise them. 

6. After they leave the body they live, but ap- 
parently they cannot multiply. 

7. They live best in damp, dark places. 

8. In such places they keep alive from a few 
weeks to two years. 

9. Bright sunshine kills them in a few hours. 

10. Boiling kills them at once. 

11. Cold does them no harm. 

1 2. They can live and float about in the driest dust. 

13. They may cause tuberculosis in any part of 
the body. 

14. They cause it in the lungs most often. 

15. Tuberculosis of the lungs is what we call 

The discovery of all these facts, one by one, was ex- 
citing to every doctor, every scientist, and every con- 
sumptive who heard about them; for each one knew 
that a turning point had come in the history of the 
disease, and that there was hope now for thousands of 
people who had been hopeless before. 

It was also clear that all sorts of people were ex- 
posing others to the disease every day, and that each 
one was blameless, for until Koch's great discovery no 


one knew the facts about the tubercle bacillus. Now, 
however, various earnest men and women learned these 
facts and studied the history of tuberculosis both in 
the country and in the city. 

Records from " Lung Block." They found that, as a 
rule, there is more consumption in places Where people 

Cliwr; 8UMt 

" Lung Block " 

The shaded paris show courts and air shafts. Each letter stands for one case of 

consumption reported since 1S94. All the "a's" belong to 1894, the "b's" to 

1895, the "c's" to 1896, etc., up to 1903 

are crowded together in dark rooms than anywhere else, 
and that even in such places there is the greatest differ- 
ence in special houses and special rooms. This was the 
case with what was called " Lung Block" in New York 
City. From these houses, during nine years, two hundred 
and sixty-five cases were reported to the health depart- 
ment, and very many more were unreported. Single 
rooms also told their sad stories. 


Mr. Ernest Poole, who studied the subject thoroughly, 
made a printed report of one of these rooms, covering a 
seven-year period. He says the room was on the third 
floor, looking down into a court, and that in it people 
died of consumption steadily, one after the other. 

1. A blind Scotchman, in 1894, ^^^ consumption, 
went to the hospital, and died there. 

2. His daughter had consumption and died. 

3. One year later a Jew was taken ill there and 
died in the summer. 

4. A German woman took the disease and died. 

5. An Irishman was the next victim. He was 
weakened by overwork, caught the disease, fought 
against it bravely, but died in 1901. 

East-Side Conditions. Another house on the East Side 
of the city had dark halls where one needed to grope his 
way about, seventy small rooms with almost no outside 
air and light, and an air shaft partly filled with rubbish 
and filth. One hundred and fifty people lived in that 
house and died fast of consumption. In the middle 
apartment on the second floor, five families were 
lodged one after the other for four years. One of the 
first family died, two from the second, and one from 
the third, while two members of the fourth family died 
in the hospital after leaving the place. 

Surely, the saddest part of such a record as this is the 
ignorance of the victims themselves. When they first 


visit the house, they notice nothing more objectionable 
than darkness, dirt, and close air. They discover no 
microbes, suspect nothing, and decide to come to the 
rooms to live. They do not know that the chances are 
that some of them have come to those rooms not to 
live but to die. 

Now how does it happen that, over and over again, 
in every crowded city, after there has been one death 
from consumption in a house other cases are almost 
sure to follow, and then still others again, for years 
and years afterwards? 

The Tubercle Bacillus : how Lodged and Distributed. 
The whole explanation is in the nature of the microbe, 
the tubercle bacillus itself. Those who examine the room 
can of course see no sign of these microbes, yet there 
may be millions of them in the dust, in the cracks of the 
floor, on the walls and the ceiling, or hidden in the folds 
of the curtains. Often all they need is to be stirred up 
by a broom that has not been dampened or to be flour- 
ished about with a feather duster ; for in either way they 
are tossed into the air and are ready to do their mischief. 

Dry dusting is bad. It simply lifts the microbes 
from the spot where they are quiet and harmless and 
scatters them in the air, where they threaten all who 
breathe it. Damp or oily dusters are best. Wet saw- 
dust or torn-up damp paper scattered on the floor before 
sweeping will keep the microbes from being scattered. 


After microbes once reach a room, they will live 
there for months and even for two years unless the 
place is thoroughly disinfected. This work of disinfect- 
ing a room or a house is so important and needs to be 
done so thoroughly that in almost every case a doctor 
or a city official must attend to it. 

The Nature of the Microbe. The very nature of the 
microbe explains all this. It has no mind. It makes 
no plans. It simply lives on when nothing kills it and 
multiplies when it finds favorable surroundings. Yet it 
never goes hunting for a home, for it cannot move 
about of itself. On the contrary, if it is in the air, the 
wind may drive it anywhere, and it will stay where it is 
tossed until something starts it moving. It is so small 
that a man may breathe it with the air. It may escape 
all the cilia and the mucus of the air passages and safely 
reach the spot where it grows the best, the lungs of a 
human being. 

Bacilli in the Lungs. Here everything is favorable. 
The place is warm and moist, the delicate tissue is 
good ground to grow in, and the microbe begins to 
multiply promptly. 

Yet there is another side to the situation. The 
lungs themselves seem to make a protest. They like 
the microbe no better than a human eye likes a bit 
of cinder. At once, therefore, certain cells of the lungs 
hurry to the spot, surround the microbe, and try to 


build themselves into a wall about it. In a way it is 
a sort of contest, and at last the multiplying microbes 
and the cells are bunched together in a hard lump 
called a tubercle. 

Sometimes the cells of the lungs are vigorous enough 
to fasten the microbes up so securely that they can- 
not multiply. In this case they become harmless, and 
the man does not have consumption. At other times 
the microbes prove to be the stronger. The tubercles 
then increase, the man's lungs gradually become use- 
less, and finally he dies. 

Danger from Sputum. Always the peril to other people 
is from what a tuberculous person coughs up. It seems 
that, as each tubercle grows larger, the center of it 
softens, and the person must get rid of it. This is the 
sputum. Often it has a yellow color and is full of 
the microbes themselves. The worse off a man is, the 
more he coughs and expectorates; and the more he 
expectorates, the more of the living, dangerous microbes 
he sends into the outer world. 

Those who know about it say that a man with con- 
sumption may expectorate two or three billion tubercle 
bacilli every twenty-four hours. 

Tuberculosis of the Bones. Instead of tuberculosis of 
the lungs, young children are more apt to have tubercu- 
losis of the bones, which gives them crooked backs and 
hip disease. This is often cured by skillful doctors. 


Consumption not inherited. Fortunately, however, no 
one inherits any kind of tuberculosis. To be sure, chil- 
dren of consumptive parents often have it, but they may 
have every chance to take it after they are born ; for they 
may live in the same house with their careless, consump- 
tive parents, may touch the same things, breathe the 
same microbe-laden air every day, and may even creep 
about on the floor, where dust and microbes are thickest. 
Worse yet, without intending the slightest harm, those 
parents may even kiss their children on the lips. They 
do not know that this should never be done. 

With thousands of careless people coughing and 
expectorating every day for months and for years, it is 
easy to understand how streets and houses, rooms and 
people, may become infected ; for each new case of a 
person who is careless with his sputum means more 
microbes to shift about, and at a moment's notice they 
are ready to go back into the lungs of any human being. 
After that, the vigor of those lungs themselves is the 
only thing that can save a man. This explains the im- 
portance of the great war between man and the microbe 
which is now being waged. 

War against the Enemy. In 1907 the Maryland Asso- 
ciation for the Prevention and Relief of Tuberculosis 
had an exciting campaign. Its rally call was, ** Will 
you help build the fence?" And for twenty-three 
days this mystic query appeared in large letters on every 


street car in Baltimore and on nearly every blank wall ; 
even the ash cans did not escape. At first there was 
puzzled curiosity on the part of those who saw the sign ; 

next came interest; and 






when the meaning of the 
question was discovered, 
when all knew that it meant 
a " fence " of prevention to 
protect people against consumption, there was such 
enthusiasm that in less than three weeks ten thou- 
sand dollars were raised for the use of the association 
during 1907. 

This, then, is the sort of warfare that is going on in 
Maryland and elsewhere in the world to-day. Now that 
we have actually found the foe, now that we know both 
how to kill him and how to protect ourselves from him, 
we are pledging ourselves to do it. We know that there 
are just two ways by means of which the world may 
banish tuberculosis: 

1. By destroying the microbes which start the 

2. By making human bodies vigorous enough to 
resist the microbes. 

In conducting this campaign, let the triple motto be: 

1. Tuberculosis is preventable ; we will prevent it. 

2. Tuberculosis spreads ; we will check it. 

3. Tuberculosis can be cured ; we will cure it. 


The Anti-Tuberculosis Crusade. With this as their 
motto men and women in all lands are now carrying 
on a world-wide anti-tuberculosis crusade. They are 
printing and distributing leaflets by the hundred thou- 
sand and the million, for they are determined that those 
who are well shall know how to protect themselves from 
the microbes of those who are ill, while at the same 
time those who are ill shall know enough not to pass 
their microbes on to others. 

The sad fact is that multitudes of people are ignorant 
both about giving and about taking the disease. Never- 
theless it is as true to-day as it ever was that the 
person who breathes dust loaded with tubercle bacilli 
is in danger of tuberculosis, and that the only way to 
escape the danger is to keep the lungs healthy and not 
to breathe such dust. 

Yet how shall we keep from doing this ? 

Careless people leave their deadly sputum in crowded 
rooms, cars, theaters, stations, and saloons. It then 
passes through all the stages of drying, being crushed, 
turning to powder, and getting into the air; and after- 
wards, in each of those places, people must breathe the 
contaminated air. In a dusty city street a man breathes 
anywhere from ten to four hundred microbes a minute, 
according to the place he is in; and the larger the 
number the greater the chance that tubercle bacilli are 
among them. 


Carelessness in Public Places. When, therefore, you see 
a man expectorate carelessly on street or floor, you have 
a right to say to yourself: "One thing is plain — either 
that man is absolutely ignorant or absolutely selfish; 
either he does not know the laws of health, the habits 
of the microbe, and the laws of the city against spitting, 
or he is willing to run the risk of giving a deadly 
disease to his fellow citizens." 

Of course it is true that saliva without tubercle bacilli 
can do no harm, but city officials know that what the 
well man does the ill man is sure to do. For this reason 
laws against spitting extend to everybody — young and 
old, well or ill — who comes where they are in force. 
Many cities post their laws in cars, stations, and all 
public places, and they enforce them or not according 
to their zeal for the welfare of their citizens. Here is a 
New York notice: 

Spitting on the floor of this car is a misdemeanor. A fine of $500, or 
imprisonment for one year, or both, may be the punishment therefor. 

Some cities are so much in earnest about this matter 
that men in tall silk hats as well as those in shabby 
derbies have been fined for breaking the law. 

Public Sentiment. A few years ago very few people 
protested; few even noticed the spitting. Now, how- 
ever, the man who spits is noticed by a dozen different 
people at once, and each one looks upon him as either 


a deserter from the camp of good citizens or as a person 
ignorant of the laws of health. 

Rules of Prevention. For his own sake, therefore, as 
well as for the sake of his city, each loyal citizen should 
practice the following rules of prevention: 

1. Never spit in a place where sputum may dry 
and get into the air. 

2. Use paper or cloth and burn the sputum be- 
fore it dries, or else use a spittoon that has water 
in it to prevent the microbes from drying and float- 
ing around in the air. Clean the spittoon often. 

3. If there is a persistent cough and a good deal 
of sputum, tell the doctor about it. He will have 
the sputum examined. 

Every doctor in the land knows how important this 
last point is, for the secret of curing consumption is to 
discover it when it begins, and the most usual way to 
do this is to examine the sputum for tubercle bacilli. 

Cure for Tuberculosis. This disease is really somewhat 
like a fire in a lumberyard. If the fire is discovered 
when it starts, a single pail of water will dash it out ; but 
if it is left until the whole lumberyard is blazing, even 
the fire department cannot save the lumber. So too with 
tuberculosis. Three quarters of the cases found early 
and taken care of are cured, while the cure itself is often 
as simple as the fire cure, although in the case of con- 
sumption four things are needed instead of one. 


1. Fresh air from morning until night and from 
night until morning. 

2. Sunshine. 

3. Wholesome food^ with fresh milk and eggs. 

4. Rest for body and mind. 

If the patient discovers the disease soon after he takes 
it, and if he can get those four things, he will probably 
recover; if he cannot get them, he will probably die. 

Safety for Others. Consumptives who are careful about 
their sputum are not in danger of giving consumption to 
others. They may live under the same roof with them, 
work side by side, breathe the same air from day to day, 
and yet, from first to last, if they destroy every drop of 
their sputum, other people are not in danger. As tuber- 
cle bacilli never fly away from a damp surface they stay 
in the throat and air tubes of a consumptive and are not 
expelled in his breath unless he breathes hard or sneezes. 
If he does either, he should hold a cloth before his mouth 
and burn it immediately or have it boiled. 

Five Tuberculosis "D's." Any person with a vigor- 
ous body is best able to resist every sort of disease mi- 
crobe. To secure such a body, let each of us learn to shun 
what have been called the five tuberculosis D's — dirty 
darknesSy dampftesSy dusty and drink. Let us also practice 
the golden rule of the anti-tuberculosis leagues: 
Dont give consumption to others. 
Dont let others give consumption to you. 


Those who understand tuberculosis best speak very 
positively about using medicines for it. They say: 

1. No medicine has yet been found that will cure 

2. Advertised medicines often contain alcohol, 
which hastens consumption. 

3. No person with consumption can afford to run 
the risk of taking any advertised medicine. 

4. In taking medicine, a consumptive should fol- 
low the advice of a good doctor. 

Then too, from first to last, they should ever seek 
those four best things — fresh air, sunshine, wholesome 
food, and rest. 

Outdoor Air. In the country as well as in the city, men 
need to know both how to prevent tuberculosis and how 
to cure it if it has made a start. Wise people will see to 
it that windows are open in their homes, their shops, and 
their schoolhouses. They will keep them open by night 
as well as by day, for they will know that less dust is 
being stirred up at night, and that night air is therefore 
the best air to be had. 

At the same time they will make sure that their bodies 
are warmly covered when they sleep in cold rooms full 
of fresh air. An inexpensive way to get extra covering 
is to sew newspapers between blankets. Paper does, in 
fact, keep cold out so well that in some places paper 
blankets are manufactured, and they can be bought by 


the dozen at a very low cost Keeping warm enough and 
breathing fresh air must go hand in hand. 

In a city even hospitals have trouble in giving a man 
all the air he needs. Windows are kept open, and re- 
clining chairs are put on the roof for certain patients 
to use. Other patients breathe fresh air even in bed. 

for the cot itself, with the patient, is thrust through 
an open window into the air and sunshine. But a sana- 
torium or a tent in the country is best of all for a tuber- 
cular patient, because in such places every needed thing 
is at hand. 

Some consumptives do not have tents, but actually 
sleep out of doors in midwinter. 


Sleeping Outdoors in Winter. Professor Irving Fisher 
says he did this when the temperature was ten degrees 
below zero. He also says that in the winter of 1904, 
in the Adirondack Cottage Sanatorium, six people slept 
outdoors when the temperature was thirty degrees below 
zero. They had two or three mattresses under them, 
warm blankets and comforters over them, heavy night 

Fkesh Air and Sunshine to cure Consumption 

clothes about them, and also woolen headgear with an 
opening for the nose. 

Each person knew that the more fresh air he could 
get, the more chance he had to live. It even seemed as 
if the colder the air the better they felt. 

Open-Air Classes. It is because of these facts that 
what are called open-air classes are springing up in 
many places. Those who start the classes know that 
every chance for life and health is increased for children 


who have been attacked by tubercle bacilli if they can 
do their studying out of doors and not within the four 
walls of a schoolroom. 

In this great anti-tuberculosis war, town and country 
people are sure to be victorious in the end, but how 
soon the end will come depends on whether or not the 
children of the world understand how serious the dan- 
ger is, and whether or not they are willing to join the 
forces that fight tuberculosis in every land. 

Let us all remember that prevention is better than 
cure, and that fresh air is as important to keep us well 
as to help cure us after we are ill. Let us make sure that 
fresh air gets into our homes by day, and that we sleep 
in abundance of it by night. Let us do what we can 
for our general health and thus help save ourselves from 
the foe without wings that comes floating to us in the 
air we breathe. And what of that other foe which may 
reach us in a glass of clearest-looking drinking-water? 
We turn now to typhoid microbes and study them in 
their natural surroundings. 


1. What was Dr. Koch's great discovery in 1882 ? 2. What causes 
consumption? 3. What is the annual death rate from tuberculosis in 
the United States? in the world? 4. In past times what has been 
the saddest part of the situation? 5. How did Dr. Koch's discovery 
bring hope ? 6. Is each separate tubercle bacillus a plant or an animal ? 
7. Tell of its shape, size, how and where it multiplies. 8. How many 


of them put end to end will measure one inch? 9. In what kind of 
places do they live best? 10. How long can they live? 11. How 
does bright sunshine affect them ? intense heat ? intense cold ? 12. What 
becomes of them in the driest dust? 13. To what parts of the body 
can tubercle bacilli give tuberculosis ? to which part most often ? 

14. What is the common name for tuberculosis of the lungs? 
15. Where is most consumption found ? 16. Describe " lung block." 
17. Mention ways in which one case of consumption leads to other 
cases. 18. Describe the conditions found in a New York East-Side 
house. 19. Where do microbes stay? 20. How do they reach the 
air from their lodging places? 21. What objection is there to dry 
sweeping and the feather duster ? 22. What should one use instead ? 
23. How does the microbe get into the lungs ? 24. What favorable 
conditions does it find? 25. In what way do the lungs seem to pro- 
test? 26. Why is sputum dangerous? 27. How many tubercle bacilli 
may a consumptive person expectorate within twenty-four hours? 
28. What articles may hold them? 29. What may become of them 
afterwards? 30. How many people inherit tuberculosis? 31. How 
do children of consumptive parents get the disease? 32. So far as 
tubercle bacilli are concerned, what especial advantage is there in 
having vigorous lungs? 

33. Describe the anti-tuberculosis war in Maryland in 1907. 
34. Mention two ways by means of which the world may banish 
tuberculosis. 35. Give the triple motto of the campaign. 36. Why 
do we make laws against spitting in public places ? 37. Give the New 
York law. 38. Why do we compel healthy people, as well as those who 
are ill, to observe the law ? 39. What rules of prevention should every 
loyal citizen practice? 40. In what way is tuberculosis like a fire in 
the lumberyard? 41. What four things are needed to cure consump- 
tion ? 42. Mention the five tuberculosis " D's." 43. What is the golden 
rule of the anti-tuberculosis leagues? 44. What can you say about 
using medicine for consumption ? 45. When sleeping in cold, fresh 
air, what must be done about keeping warm ? 46. How do city hospitals 
manage to give their patients fresh air ? 



Former Conditions in Pittsburgh. Year after year, for 
thirty-five years, people died in Pittsburgh, Pennsylvania, 
under the scourge of typhoid fever. As the city grew, 
the number of deaths multiplied until, in 1907, 622 
people died of typhoid alone. 

But the misfortune was greater than this ; for, besides 
those who died, there were thousands of other people 
who suffered but did not die. Hundreds at a time were 
ill in their homes and in the hospitals of the city. They 
lost money because they could not work for daily wages. 
They paid out for doctors' bills and medicine savings 
that were intended for food, fuel, clothing, and house 
rent. Thousands of children were hungry and cold be- 
cause their parents were too ill to care for them and too 
weak to work. It is indeed estimated that for each 
person who dies of typhoid fever eight other persons 
are ill with it. 

Explanation of the Death Rate. So matters progressed 

from bad to worse for thirty-five years. In the meantime 

a generation of people came and went. And what was 



the explanation of this death rate? Just one thing. The 
drinking-water of Pittsburgh. Why, then, did the citizens 
use it? Because at that time multitudes of people did 
not know the facts about pure and impure drinking- 
water. They did not know that every case of typhoid 
fever is started by a small living thing which comes 
from the body of some one who has the fever. They did 
not know that this microbe is harmless unless it gets 
into our mouths and we swallow it alive. They did not 
know that their own drinking-water was loaded with 
living, active typhoid microbes which had come direct 
from the bodies of other people. They did not even 
know that boiling kills disease microbes, and that any 
boiled water, no matter how wretched it looks, is safe to 
drink because it is free from living typhoid microbes. 

And just because they were ignorant, multitudes of 
honest, hard-working people in Pittsburgh took city 
water as it came from the faucet and drank it without 

How Typhoid Microbes reached Pittsburgh. Perhaps 
we wonder why this particular water was so full of the 
microbes. Any map of that section of the country helps 
us to find the explanation. Notice the location of Pitts- 
burgh. See how it lies at the point where the Allegheny 
and Monongahela rivers join to form the Ohio; Follow 
the two streams upward and notice that all the way 
along towns and cities are ranged on both banks of both 


streams. There are over seventy-five of these groups of 

houses, and their united population gives a total of over 

350,000 human beings. This, then, throws light on the 

entire water problem of Pittsburgh, for it turns out that 

each of these towns and cities 

pours all its waste water, its 

sewage, into the river on whose 

banks it stands. A most natural 

riddance of it surely, for the 

river carries off the waste, taking 

it downstream. But think of the 

next step in this water history. 

Not only does each town empty 
all its sewage into the river, but 
each town also takes all its drink- 
ing-water from the same river. 
In other words, the sewage of 
each town becomes pari of the 
drinking-water of all the towns 
that lie farther downstream. 
Naturally the mixture grows con- 
stantly worse, and by the time 
it reaches Pittsburgh it is fearful stuff to drink. 

Nevertheless, just as it was, without any pretense at 
killing the microbes or taking them out, this liquid 
compound of water, waste, and filth was in those days 
turned directly into the huge water pipes of Pittsburgh, 


and the masses of the people drank it with no suspicion 
of danger. Had they known the peril and the way of 
escape, they would have saved themselves. 

Microbes and Drinking-Water. We ourselves know that 
if there are no typhoid microbes in our drinking-water, 
however wretched its color and taste may be, it cannot 
by any possibility give us typhoid fever. We also know 
that however clear and sparkling it may be, if there are 
typhoid microbes in it, disease and death may go to the 
one who drinks it. In the case of Pittsburgh, many 
persons upstream had typhoid fever, and their sewage, 
with its load of microbes, was poured into the stream 
and sent from city to city as the stream rolled onward. 
Pittsburgh suffered most simply because it was farthest 
downstream and had therefore received more sewage in 
its drinking-water than any other place. 

Safety through Sand Filters. Then came an abrupt, 
astonishing change in the death record. During the 
single month of October, 1907, 596 persons had been ill 
with the fever. But during the month of October, 1908, 
there were but 96 cases of it in the city ; and deaths for 
the entire year dropped off in like proportion. This 
changed record has continued to the present day. And 
the explanation of the entire change rests with the sand 
filters which were set to work in 1908. These filters are 
near the city, 46 in number, and worth visiting. Each 
covers an acre of ground; each is about five feet deep; 


each is a separate bed of pebbles, gravel, and fine sand 
— pebbles on the bottom, sand on top. River water 
is turned on these filters. It soaks through slowly and 
is carried in water pipes to the homes of Pittsburgh. 
Nothing could be more unpretentious and matter of fact 
than those huge sand filters.^ Yet 
they are the life-saving stations of 
the city. They purify the water 
and, by so doing, save hundreds of 
lives each year. Scores and scores 
of towns and cities are saving 
themselves by the same sensible 
method. At the same time, multi- 
tudes of other townspeople are 
drinking unsafe water. Most of 
them do this ignorantly. 

Now think for a moment of the 

Sand Filtek water conditions in your town. 

rom coarse^grave o ne -^^here docs your drinking-water 

come from? If from a river, study 

some map and try to decide whether or not other people 

farther upstream are sending their sewage down to you. 

' Multitudes of microbes live and multiply on the surface of large, out-of-door 
filters. They find their best food in the worst kind of water and sewage. When 
water is poured upon a filter bed, these hungry microbes take the impurities out, 
and also destroy disease microbes — and other kinds too — that were in it After 
this, the water is safe to drink. Thus it is that microbes on the sand purify Our 
water for us, and save us from disease microbes. 


If SO, when typhoid fever attacks any person in that 
town, you yourself will be in danger. Clearly enough, 
then, all river water that is exposed to human contami- 
nation should be either boiled or sent through outdoor 
sand filters before it is used as a drink. A small filter 
in the house does not purify water in the same way. 
It takes out dust and color, but it does not remove 
disease microbes. 

Lake Water for Drinking. Perhaps your drinking- 
water comes from a lake. If no human beings send 
sewage of any sort into that lake, water from it may 
be used fearlessly as a drink. Generally, however, large 
lakes receive much sewage from houses and towns that 
stand on their shores. For safety's sake, then, such lake 
water should be either boiled or filtered. 

Danger from Well Water. Perhaps you draw water 
from a cool country well and feel very safe as you drink 
it. Still there may be danger even here. For example, 
two friends enjoyed what they considered delicious 
water from a country well in northern Ohio. One month 
later both men were down with typhoid fever and one 
of them died. What was the trouble? Those who 
examined the surroundings afterwards saw that the well 
was too near the dwelling house to make it safe. Water 
from the surface of the ground found its way into the 
well, and with it had gone sewage from a man who had 
had typhoid fever in the house. The water itself was 


cool and clear as crystal. Neither by its taste, its color, 
nor its odor did it tell any tales about Itself. Dangerous 
microbes were, however, concealed in it. This peril from 
well water is so real that many a village which depends 

Notice that both well and cesspool are near the house. The contents of the cess- 
pool soak through the ground without hindrance and contaminate the water which 
supplies the well. If typhoid microbes are in the cesspool, they will get into the 
{From The Human MechanUm, by Hough and Sedgwick) 

on wells is more in danger from typhoid fever than are 
large cities which supply themselves with water brought 
to town through pipes from some pure though distant 

Sources of City Water. Judging by the facts, then, 
it begins to look as if water were encompassed by 


danger. So it is wherever sewage from man can in 
any wise reach it. For this reason we have all grown 
more careful about the sources' of our water supply. 
Some cities draw it from mountain springs and from 
small lakes which cannot be contaminated by man. 
Others build huge reservoirs and protect them. Here 
water is stored by the hundred million gallons at a 
time. Still other places yet filter such water as they are 
obliged to use from undesirable sources. For example, 
London, in England, must use water from the Thames. 
Yet, as this river flows by, it carries sewage from 
many towns on its way to the sea. Nevertheless even 
the terrible water of the Thames is so purified by 
sand filters that London is remarkably free from 
typhoid fever. 

It is unpleasant to use unclean drinking-water, but as 
already shown, the real danger to life is from the disease 
microbes which may be in it. They may give typhoid 
fever and other intestinal troubles. As a safeguard 
against typhoid fever, doctors now inoculate people and 
thus protect them. 

Rain Water. It is raining at the present moment, 
and I think of the pure water that comes from the 
skies. Not a microbe is in it, for microbes never 
ascend to the clouds when water evaporates. Float- 
ing microbes may be in the air on a dusty day, but 
these are washed out by the first dash of raindrops. 


Everywhere in the world, therefore, rain water, direct 
from the sky, is safe to drink. And when this water is 
caught in clean tanks and kept away from all human con- 
tamination, it continues to be the safest water we have. 

In deciding whether to live in this town or that, always 
make some inquiry about the water supply before you 
come to any decision as to where to make your home. 
For life itself depends on the purity of drinking-water. 

Typhoid Epidemic from Milk. Then, too, there is that 
other important drink — the milk we use so constantly. 
Even in this there may be danger from harmful 
microbes. In Springfield, Massachusetts, in 1882, typhoid 
fever suddenly appeared in several different homes at 
about the same time. On investigation it was found 
that all who had the fever took milk from the same 
milkman, and a little later it also appeared that a man 
had just had typhoid fever in the milkman's home. 
Just how the microbes reached the milk no one could 
say. Perhaps the milk cans were washed in contami- 
nated water. Perhaps typhoid microbes were on the 
hands of the man who did the milking. However it 
was done, there was no doubt about the fact. In one 
way or another typhoid microbes had reached the milk 
and passed the disease on. Scarlet fever and other 
diseases have sometimes been carried in the same 
way. But it is typhoid microbes that threaten milk 
most frequently. 



Conditions of Clean Milk. In the town where I live 
there is just now quite a rivalry in the milk business. 
Two men are trying to outdo each other in the per- 
fection of the milk they deliver. On one neat-looking 

A Model Dairy 
Clean cows, clean stables, and clean milk 

milk wagon the printed sign reads, "Clean Milk 
Dairy"; on the other there are but two words, "Pure 
Milk." As for ourselves who buy the milk, we know 
that from both wagons the best of milk is delivered to 
us. We are sure of this because both dairies believe in 
cleanliness, and try to secure it. They know that the 


cleaner the milk the fewer the microbes^ the fresher the 
milk the fewer the microbes^ the colder the milk the fewer 
the microbes. 

In both dairies, therefore, clean cows are kept in 
clean stables; they are milked by clean men, who 
wash their hands before they do the milking. Clean 
pails, clean pans and bottles, all are kept fresh and 
sweet through the use of boiling water and "live 
steam." Those who conduct this business know that 
microbes multiply faster in warm, unclean milk than 
elsewhere, and that each speck of mud, each bit of 
horsehair, that enters the milk carries countless mi- 
crobes with it. They also know that each of these 
microbes begins to multiply at once and that no 
amount of straining can take out microbes after they 
are once in a liquid. These men are therefore wise 
enough to be careful of the milk supply from the 
time it is drawn until it is delivered. In addition, 
they keep it cool from start to finish. 

Unclean Milk. It is quite otherwise, however, with 
certain men who carry on the same important business 
in a neighboring town. They do not seem to know that 
dirt and microbes go together, that the more dirt the 
more microbes^ that tJte older the m^ilk the m^ore microbes^ 
that the warmer the milk {before it is cooked) the m^ore 
microbes of many kinds will be in it. As a result their 
milk is not such as we should wish to use. 


Boiling Milk to kiU Microbes. If at any time you are 
not sure about the history of your milk supply, and if 
you wish to make it perfectly safe, remember the old 

Clean Milk for Rochestek Babjks 

lesson that boiling kills microbes wherever they are. 
Two things may render milk harmful: 

1. The presence of disease microbes which may 
reach it through carelessness. 

2. The presence of too great a number of mi- 
crobes which are harmless in themselves. 


Pure Milk for Babies. For young babies this last 
danger is the real one. Various cities are beginning to 
take this fact into account and are trying to supply the 
babies of the city with milk which carries as few mi- 
crobes as possible and no danger whatever. By means 
of pure milk the city of Rochester, New York, reduced 
the death rate of its babies from locx) in 1892 to less 
than 500 in 1 904. Thus one example is added to another 
and, the world over, fathers and mothers are learning 
that the kind of milk they buy helps decide what the 
death rate of their youngest children shall be. It is 
indeed the children who suffer most through the igno- 
rance of their elders. The next chapter proves this. 


1. What special disease became a scourge in Pittsburgh ? 2.. How 
many died of typhoid fever in 1907 ? 3. How did other people suffer 
from the disease even when they did not die? 4. How long did the 
scourge last? 5. What caused it? 6. How could it have been pre- 
vented? 7. Why was it not prevented? 8. Tell what you can about 
the typhoid microbe itself. 9. How does it get into the body ? 10. What 
do towns on the banks of the Allegheny and Monongahela rivers do 
with their sewage? 11. Where does their drinking-water come from? 
12. Why was Pittsburgh water worst of all?' 13. What one thing is it 
that makes water unfit to drink ? 14. Describe the change that came 
in the Pittsburgh death rate in 1908. 15. What explained the change? 
16. Describe the Pittsburgh sand filters. 17. What do they do to water ? 
18. Where does your own drinking-water come from ? 19. Why is river 
water generally unsafe to drink ? 20; Why is water from a lake unsafe ? 


21. When is well water unsafe? 22. How can sewage get into a 
well? 23. What do cities do for water? 24. Tell about London water. 
25. Why is rain water safe to drink ? 

26. Describe the typhoid epidemic in Springfield. 27. Describe the 
difference between clean milk and unclean milk. 28. How do microbes 
get into milk? 29. Why should milk be clean, fresh, and cold? 30. In 
what sort of milk do microbes multiply fastest? 31. How can unclean 
and unsafe milk be made safe to use ? 32. Mention two ways in which 
harm may come through microbes in the milk. 




Preventable Diseases. In every country and in all 
parts of the world, men, women, and children are asked 
to join the modern army and help wage the modern 
war against the following preventable diseases : tubercu- 
losis, typhoid fever, measles, smallpox, scarlet fever, hy- 
drophobia, whooping cough, pink eye, trachoma, malaria, 
yellow fever, pneumonia, the hookworm disease, and our 
everyday colds. 

As we study the list let us bear in mind three facts: 

1. Disease microbes are killing more human be- 
ings each year than are being killed in any other 

2. Those who die of any disease are few in com- 
parison to those who suffer from it. 

3. If we were all careful enough about preven- 
tion, our preventable diseases would soon be wiped 
out of existence. Think of the difference this would 
make in the happiness and the welfare of the world. 
Yet carelessness often comes through ignorance. 

Take the following case for example: 



Measles and Scarlet Fever. A boy in New York City 
who thought he had measles^ went to bed, called the 
doctor, stayed at home for some time, then was well 
again and went back to school. After that he became 
very popular. Why? Because, as Mr. Riis says, "He 




Scarlet Fever. 

When the danger from infection has Passed this 
card will be removed. 

Any Person removing this card without authority 
is liable to a fine of One Hundred Dollars. 

Placed on a House by the Board of Health 

could pull the skin off with his fingers as one would 
skin a cat." And he gave the largest rolls to his dearest 
friends. He did not know and his friends did not know 
that disease microbes are thick in each smallest frag- 
ment of skin that comes from any one who has had 

^ Mr. Riis, who tells the story, says the boy had the measles. But critics think 
the disease must have been scarlet fever, because the peeling and the danger 
from the skin is much greater after scarlet fever than after measles. 


measles or scarlet fever. So the skin went from the 
boy to his friends. They took it home with them and 
divided it among their other friends. 

Then came the climax. A great spreading epidemic 
broke out wherever the skin had been distributed. 
Many were ill; some died; all suffered. If those boys, 
their parents, and their friends had known the facts 
about measles, they would have used their brains and 
saved their bodies from a very preventable epidemic. 

Here are a few of these facts : Both measles and scar- 
let fever are known as eruptive diseases because they 
cause eruption of the skin. After this the dead skin 
peels off in bits. The victim should not mix with other 
people until the so-called " peeling " is well over, for 
those harmless-looking bits of dead skin may be alive 
with danger, and nothing but isolation of the patient 
can keep him from scattering disease. It is necessary 
to take special care of the eyes while recovering from 
either scarlet fever or measles. 

Smallpox. There is another contagious disease which 
is far more terrible than measles. In the year 1854 this 
disease broke out on Ponape, one of the Micronesian 
islands. It came from the garments of a sailor who 
had died there of smallpox. At the time of his death 
Ponape had a population of ten thousand; but six 
months later half of those ignorant islanders were dead 
and buried. The microbe of smallpox had slain them 


before they had had time to learn how to protect them- 
selves from this preventable disease. 

In former times people dreaded smallpox and fled 
from it. They knew it was contagious and realized what 
its results were; but they tried in vain to escape it. 
Though they fled, they were overtaken by it; they suf- 
fered from it and carried the marks of it on their faces 
until they died. They were also killed by it by the hun- 
dred thousand every year. According to a careful calcu- 
lation, fifty million Europeans died of smallpox between 
the years 1700 and 1800. 

Then at last an Englishman, Dr. Jenner, learned how 
to save men by vaccination. Since that time smallpox 
has slipped into the background of the deadly diseases 
of the world. The explanation is that to-day in every 
civilized country vaccination has been adopted as a pre- 
ventive. It is true that nowadays people feel so safe that 
they often grow careless. Even the mothers of the chil- 
dren sometimes forget to have their sons and daughters 
vaccinated. In such cases, however, the board of health 
of the city or town often steps in and gives commands. 
This was done by New York City in 1901. Without 
much warning smallpox had appeared in the place.- Peo- 
ple here and there who had not been vaccinated were 
down with the ^ fever and were dying. Two hundred 
special inspectors were appointed at once, and within 
six months eight hundred and ten thousand people, 


young and old, had been vaccinated, and the city was 
saved from what would have been an epidemic more 
frightful than that which swept over Ponape. For in a 
city human beings are crowded so close together that 
microbes have a chance to spread fast Vaccination is, 
however, such a sure road of escape that certain cities 
compel all the children to be vaccinated before they let 
them go to schooL 

Diphtheria. Here, also, we have a swift-moving disease 
which seems to fly from house to house through the 
power of an unseen foe. We ourselves know that in this 
case too the invisible power is a microbe, which takes 
its start within the throat and is able to kill its victim. 

As it happens in any attack of diphtheria, life de- 
pends on the speed with which prevention can overtake 
the microbe as it multiplies. A child has a sore throat, 
then a fever. The doctor is called, and if he finds all the 
signs of the dread disease, he knows that his one hope is 
to kill the microbes before they can kill the child. With- 
out a moment's delay, therefore, he uses the one great 
cure for diphtheria — antitoxin. He not only puts this 
into the body of the child who is ill, but also gives it 
to each person who has been an)rwhere near the child. 
Indeed the infection itself passes so swiftly from one to 
another that the only safety is to use antitoxin on all 
alike. It not only helps cure the one who has the dis- 
ease, but also protects those who have been exposed to 


it. In previous times about forty of every hundred who 
had diphtheria died of it. Now it kills not more than 
eight in each hundred. The difference in the. death rate 
is explained by the power of antitoxin to save those who 
have been attacked by the microbe. 

Hydrophobia. In still another terrible disease, antitoxin 
of another sort plays an important part. 

Not long ago the newspapers reported the sad case of 
three persons who had been bitten by a mad dog in a 
country town. He had been a good-natured dog, and no 
one suspected danger until he had bitten one boy and 
two men. He was then caught and mercifully killed. 
And what of the men and the boy ? The doctors in the 
place knew that there was hope of life for them if they 
could be treated with an antitoxin prepared for just such 
cases, for it destroys the power of hydrophobia microbes 
after they have been put into the body by the teeth of a 
mad dog. All three of the victims were therefore hurried 
to Chicago. There they were treated at a special hos- 
pital for such cases. One man had been a little slow 
in arriving, and he alone suffered from the disease. The 
other man and the boy were saved by the antitoxin, 
which was given in time. Perhaps no suffering is more 
dreadful and no death much sadder than that which 
comes through hydrophobia. But in these days this dis- 
ease is preventable, for large cities in all parts of the civi- 
lized world prepare antitoxin and supply it to the doctors 


when needed. This method of cure was one of the great 
discoveries of Louis Pasteur, the French scientist. 

Ddgs are not the only living creatures that put mi- 
crobes into man by cutting through his skin. Turn to 
the havoc which mosquitoes have wrought. 

Yellow Fever and Malaria. In 1793, within the space 
of six and a half weeks, one tenth of the population of 

Philadelphia died of yellow fever. 
Naturally, of course, the city was 
in a panic. No one knew what 
started the fever nor how it trav- 
eled from one person to another. 
But, thanks to science once again, 
we now know that if every mos- 
quito of a certain kind were ban- 
Stegomyia Mosquito that ished from the earth to-day, no 

CARRIES Yellow Fever , , . , , . , 

human bemg would ever agam be 
killed by yellow fever. It has been proved that stego- 
myia mosquitoes are the only yellow-fever agents in the 
world. By their sting, provided they themselves have 
already stung a yellow-fever patient, they pass the disease 
along. Malaria is another disease whose contagion is car- 
ried by mosquitoes alone. A person who was never stung 
by the anopheles mosquito would never have malaria. 
But that same anopheles must first sting a malarial fever 
patient before he himself will have the microbes to 
pass along. Other kinds of mosquitoes do us no harm 



whatever, but all kinds look so much alike that our path 
of duty is plain. We must therefore try to keep from be- 
ing stung by any kind of mosquito. In order to banish 
them, we must prevent their eggs from hatching, must 
get rid of standing water where eggs may be laid, and 
must destroy all mosquito wrigglers. Many cities are 
doing these things. Small 
ponds and marshy places 
are drained or filled with 
earth. Barrels and tanks 
holding water are closely 
covered. Cans, bottles, and 
discarded kettles which 
might hold water after a 
rainstorm are not left where 
mosquitoes can reach them. 
Kerosene oil is poured over 
ponds containing eggs and 
wrigglers. This oil suffocates the wrigglers before they 
have time to turn themselves into full-fledged mosquitoes. 
The Hookworm Disease. So much for our flying foe, 
but what shall we say of the hookworm, that other foe 
that creeps and crawls, and bores its way into the skin ? 
In this case our objection is to the creature itself and 
not to any microbes which he may put into us. Fortu- 
nately for mankind, a modern discovery shows how even 
hookworm disease may be prevented and cured. 


Above is anopheles that carries malaria. 
Below is culex, the common, harmless 
mosquito. We know which is which by 
the position each takes when resting 


The worms themselves get into the body in two ways : 

1. Through the skin. They work their way into 
bare feet that tread upon them; they prick their 
way into the hands of those who handle them. 

2. Through the mouth on things that are eaten 
or in water that is swallowed. 

When they enter the body they are so young and so 
small that they cannot be seen except by the help of a 

After they are in the body they travel hither and 
thither in the blood stream until they reach the long 
tube of the digestive canal. They like the small intes- 
tine best, and here it is that they earn their name, for 
they hook themselves to the lining of the tube with their 
mouths, suck up blood, even eat the lining itself, and 
finally grow to full size — half an inch long and as large 
round as No. 8 cotton thread. As many as three thou- 
sand of these have been found in one person. 

When they are really full-grown they lay their eggs 
by the thousand. But these eggs never hatch within 
the human body where they were laid. Instead, they 
are sent out of the body with the other refuse, and the 
hatching is done in the outside world. 

Later, when the young hookworms are partly grown 
(although still of microscopic size), they enter any human 
skin within reach. If they do not get the chance to do 
this, they are bound to die without descendants, for 


hookworms never lay eggs anywhere except in the 
bodies of living human beings. 

The real objection to having hookworms within us is 
that they suck up so much blood for their own use that 
the owner of the blood suffers for lack of it. When this 
happens we say that he has hookworm disease. 

Children suffer most During the time that hook- 
worms are robbing them of their blood they grow at 
a snail's pace and are languid, listless, and poorly 
developed. They have what are called pulsating blood 
vessels in the neck, and a tallowlike skin. Hook- 
worms cause it all. Indeed hookworm disease affects 
nerves, muscles, lungs, blood and circulation, stomach 
and digestion. 

When the worms are outside the body they thrive best 
in warm, moist, sandy soil. Naturally, therefore, the dis- 
ease is more common in summer than in winter and far 
more prevalent in warm regions of the earth than in 
places that are sometimes wintry cold. 

Very often hookworm disease starts with what is 
called ground-itch. In fact, the spot that itches is gen- 
erally nothing but the place where the worm pierced 
the skin and entered the body. Sad to say, in parts 
of the earth that are constantly moist and warm there 
are to-day thousands of men, women, and children who 
are victims of this hookworm disease. But doctors can 
cure the disease and prevent its return. 


1. They give one kind of medicine to kill the 
worms within the body. 

2. They give another kind of medicine to help 
the body drive dead hookworms out of it. 

3. They see to it that refuse which passes from 
the human body is put where no worms hatching 
out from the eggs that may have been in it can 
ever get into the neighborhood of human beings. 

4. They teach people not to go barefoot; not to 
wear leaky shoes ; not to put the hands into soil that 
may hold hookworms ; and not to drink water that 
could have been reached by hookworms. 

In doing all these things, scientists are keeping in 
mind two facts: 

1. To prevent hookworm disease, hookworms 
and human beings must be kept apart. 

2. The way to keep them apart is to prevent 
human refuse from reaching any soil which may 
be walked upon, and from reaching any water that 
may be used for drinking. 

To secure these results, houses must be connected 
with a sewer system that carries all human waste to 
some distant point. When this is impossible, houses 
— whether private homes or schoolhouses — must each 
have what is known as a sanitary outhouse. In other 
words, the one important point is to keep the ground 
free from human pollution. And the one danger from 


this pollution is that it may have hookworm eggs in it 
by the hundred and the hundred thousand. 

Rules for those living in Hookworm Regions. The 
following medical commands must be obeyed by all 
who live in hookworm regions : 

1. Stop soil pollution. 

2. Build and use sanitary outhouses. 

3. Never go barefoot unless the ground is 
perfectly dry. To state it the other way round: 
always wear shoes when it is raining, when the 
ground is wet, even when dew is on the ground. 

Going barefooted on wet ground in hookworm re- 
gions gives hookworms their chance to enter the body. 

4. If you get ground-itch, go to the doctor about 
it at once. Always take treatment for hookworm 
disease within three months after you have had 
an attack of ground-itch. 

Whooping Cough and Mumps. From such an unpleas- 
ant subject as hookworm disease, it may be a relief to 
turn to whooping cough and mumps. Here again we 
have two diseases that reach us through the air. While 
you have either trouble, stay by yourself or with others 
who suffer similarly. Do not mix with well people until 
the doctor allows it. Never forget that when you cough 
you throw impurities into the air, and that those who 
breathe the air afterwards will draw these impurities into 
their lungs. He who has whooping cough or mumps 


should use his own particular knife, fork, spoon, cup, and 
tumbler until he is altogether well — unless, indeed, he 
boils them all after using them. Boiling will make them 
safe for others to use. Perhaps the worst thing about 
whooping cough is that those who have it are more 
easily overcome by other diseases afterwards. 

Pneumonia. The same is true of that dread disease 
pneumonia. The word itself frightens those who know 
most about the disease. They tell us that pneumonia kills 
more people each year than any other single disease ex- 
cept tuberculosis. It takes young and old alike. Here,, 
as in consumption, the microbes multiply with extraor- 
dinary speed. And while they multiply they produce a 
poison which is deadly enough to kill the strongest man. 
The microbe of this disease gets into the air from the 
lungs of any one who has pneumonia. Those who have 
it must therefore stay in quarantine until they are welL 
At the same time, whatever comes from the mouth must 
be destroyed as carefully as if the disease were tubercu- 
losis. Pneumonia usually starts when one has a cold, or 
is overtired, or has spent time in badly ventilated, 
crowded rooms. It also comes easily after some other 
disease that has left the body weakened. In order to 
escape pneumonia, then, and also to escape every other 
disease, the great line of defense is to keep the body in 
vigorous condition. The way to do this is to be faithful 
in following the general laws of health. 


Pink Eye and Trachoma. In the schoolroom, however, 
even very healthy children may have pink eye or 
trachoma if they are careless about the microbes of 
these diseases. 

The former is a nuisance ; the latter is a very serious 
eye disease. Both afflictions often travel by the road of 
the public towel. If any child in a public school has a 
contagious eye trouble and uses the school towel, he 
will leave his eye-disease microbes on it. Later these 
same microbes will be left on the eyes of other children 
who use this towel. When an epidemic of eye disease 
is actually started, do not touch your hands to your 
eyes. Microbes may have been left on books, pencils, 
and desks by persons who have touched their diseased 
eyes with their hands. By handling the same things 
you may take the same disease unless you are strictly 
careful to keep your hands away from your eyes. All 
this restates facts given in Chapter XIX. 

Disinfection and Antiseptics. We should also know 
that after any contagious disease, the room or the house 
should be thoroughly disinfected. This means that all 
the microbes of the special disease must be killed in 
order to save human beings from infection. The doctor 
or some other experienced person should attend to this 
matter, for the disinfection of a house is not the simple 
affair which some people imagine it to be. Unless it is 
thoroughly done, it is useless. 


As a rule, antiseptics are used to destroy microbes 
on the body. A disinfectant is stronger and is used not 
on the body but on clothes, rugs, etc., where microbes 
must be killed. 

In addition to all else, let us never forget that the 
health of the body demands two great things of us: 

1. That we destroy disease microbes (tubercle 
bacilli, t)^hoid microbes, and all the others) before 
they have any chance to attack the body. 

2. That we keep the defenses of the body in such 
vigorous condition that even if disease microbes 
enter, they will not conquer us, but will be con- 
quered by us. 

In other words, our war against the microbe means 
that we should do two things, and that we should do 
them both at the same time: 

1. Fortify the body. 

2. Exterminate the foe. 


.1. Mention some diseases which the modem, army fights. 2.. If 
everybody were careful, what would happen to our preventable diseases ? 
3. What danger was there in the skin the schoolboy distributed ? 4. How 
long should the victim of an eruptive disease" — -measles, etc. — stay away 
from other people? 5. Describe the smallpox epidemic on Ponape. 
6. What did smallpox do in Europe between 1700 and 1800? 7. What 
was Dr. Jenner's discovery in 1796 ? 8. What keeps us. safe from small- 
pox nowadays? 9. Describe vaccination in New York City in 1901. 
10. Why do epidemics spread fastest in crowded places? 11. Where in 


the body does diphtheria start? 12. In diphtheria, what must be done 
at once? 13. Why is there haste? 14. To whom is antitoxin given? 
Why ? 15. What was the former death rate from diphtheria ? the death 
rate now ? 16. What should be done for a person who has been bitten 
by a mad dog ? 17. Why is delay dangerous ? 18. What epidemic swept 
Philadelphia in 1793 ? 

19. What causes yellow fever? 20. How may it be banished from 
the earth ? 21. To pass the disease on, what must the stegomyia 
mosquito first do ? 22. Name another disease carried by mosquitoes. 
23. Which mosquito carries malaria? 24. How does the anopheles 
mosquito get the microbes which it carries ? 25. Why must we protect 
ourselves from the sting of the mosquito? 26. What are cities doing 
in this line? 27. Why do they pour kerosene oil over stagnant ponds? 
28. How do hookworms enter the body? 29. Where in it do they 
start? 30. How do they travel about? 31. Describe their feeding; 
their size. 32. Where do they lay eggs ? 33. Where do the eggs 
hatch? 34. In what ways do people suffer from hookworms ? 35. When 
outside the body, where do they thrive best ? 36. Is hookworm disease 
more common in summer or in winter? 37. In what regions is it most 
often found? 38. What is ground-itch a sign of? 39. What should 
be done with human waste to avoid spreading hookworm disease? 
40. Give medical commands to be obeyed wherever hookworms are 

41. How do whooping cough and mumps reach us ? 42. What is said 
about knife, fork, spoon, etc. ? 43. Why is pneumonia such a serious dis- 
ease ? 44. Whom does it attack, the young or the old ? 45. How fast do 
pneumonia microbes multiply ? 46. What do they produce ? 47. How do 
they get into the air ? 48. How should the patient protect the air from 
contamination ? 49. What is the great defense against pneumonia and 
every other disease? 60. Which eye diseases may be caught in the 
schoolhouse? 51. Why should we shun the public towel? 62. How 
may we save ourselves from eye disease? 53. Who should attend to 
the work of disinfection ? 54. What two great things does the health of 
the body demand of us ? 



Cholera Microbes and the Phagocjrte. Scientists have 
known for a long time that the red blood corpuscle is 
the oxygen carrier of the body, but for years they came 
to no final conclusion about the occupation of his busy 
companion the white blood corpuscle, the phagocyte ^ — 
• ' the devourer," as his name means in Greek. The 
mystery vanished, however, when Professor Metchnikoff, 
of the Pasteur Institute, in Paris, turned his attention 
to the subject. 

He took a healthy frog, carefully pricked some cholera 
microbes under its skin, and with his microscope watched 
the fate which befell them. The whole affair was easy 
to follow, for as soon as the cholera microbes entered 
the blood stream, white phagocytes flocked to the spot 
from all sides; they crowded close; each seemed to 
choose its special victim, and drawing closer yet, laid 
itself alongside its enemy, stretched itself into a new, 
curved shape, and little by little wrapped itself about 
the doomed microbe. 

1 All phagoc3rtes are white blood corpuscles, but there are also white blood 
corpuscles that are not phagocytes. 




How the Phagocyte captures Microbes. The phagocyte 
is really nothing more than a tiny round speck of living, 
active, independent substance called protoplasm, but it 
captures its victims relentlessly. In vain the microbes 
seemed to try to flee ; their captors had surrounded 
them completely and held them firmly within their own 
bodies long enough to digest them. Instead of killing 
an enemy outright and throwing 
him aside, they rid themselves of 
him by swallowing him whole. 
Quickly hurrying to another, each 
phagocyte repeated the process, 
disposing of one microbe after 
another and growing larger with 
each captive. 

When the intruding microbes 
were small enough to make it pos- 
sible. Professor Metchnikoff saw 
the phagocyte " swallow them in 

shoals as a whale swallows herring." Whereas if they 
were too large for one to manage alone, several phag- 
ocytes would surround the same microbe and digest 
him in partnership. 

In this connection it is interesting to know that a 
frog never dies of cholera. The reason is clear — frog 
phagocytes are so vigorous that they conquer cholera 
microbes before the latter have a chance to manufacture 

Shapes which One Phago- 



their deadly toxin and give cholera to the frogs. In the 
same line of investigation Professor Metchnikofif next 
discovered that pigeons cannot be made to take tuber- 
culosis, for here again, when he introduced tubercle 
bacilli into a pigeon's blood, the phagocytes seized 
them as fast as they entered the body and devoured 
them before any harm was done. 

The work which the phagocyte does for the body is 
so valuable that we are easily tempted to talk about this 
free-swimming single cell as if it were a soldier fighting 
our battles. In point of fact, however, and even though 
they do behave like friend and foe, there would seem to 
be no real enmity between the phagocyte and the microbe. 

How Phagocytes Travel. These small protectors of the 
body move from place to place in independent fashion. 
They spend most of their time in the blood, and in 
it they not only travel with the current but they also 
ignore the current entirely and, like the salmon, swim 
upstream as well as downstream, as occasion may 
require. At a moment's notice, also, they can leave 
the blood and pass through any bodily tissue without 
the slightest difficulty. 

Vigorous and Feeble Phagocytes. Through Professor 
MetchnikofFs experiments, and others since then, facts 
have been learned which help human beings. If our 
phagocytes are strong enough to destroy disease mi- 
crobes for us, we shall be saved from certain serious 


diseases. If, on the contrary, our phagocytes are feeble, 
or if microbes enter our body in such swarms that 
there are not phagocytes enough to fight them suc- 
cessfully, the enemy will be victorious, the phagocytes 
will be defeated, and we shall be the victims of any 
disease microbes that may attack us. Put two men 

Influenza Microbes 

On the left, as they are found in the sputum of Eome colds ; on the right, 

as they are raised in the laboratory 

into a town where cholera is working havoc; let 
one have more vigorous phagocytes than the other, 
and he will be the one more likely to escape with 
his life. Let measles or pink eye, whooping cough 
or influenza, break out in school, and those children 
with the most numerous and active phagocytes will 
suffer the least. Let tubercle bacilli be thick in the 


dust we breathe, and those of us who own the best 
bodyguard of well-developed phagocytes will be least 
likely to take the disease and to suffer from tuber- 
culosis afterwards. 

The same law holds true even for less serious illness. 
When some one says, " I am so sensitive, I catch cold 
at the least exposure," it is quite as if he said, " My 
phagocytes are wonderfully weak and inefficient; they 
are vanquished by all the microbes of influenza that 
enter my body." Another person says, " I never seem 
to take cold," and it is as if he said, " My phagocytes 
are such valiant warriors that they destroy every 
intruding microbe." 

The Phagocyte as a Scavenger. Yet the phagocyte is 
not merely an athletic policeman and a valiant soldier; 
he is also a scavenger and a street cleaner that never 
seems to be idle. Here and there through the body 
he hurries, always trying to remove waste matter and 
to destroy intruding microbes. 

You cut your hand, or you run a sliver into your 
finger, and from every side phagocytes hasten to clear 
away the rubbish and to attack the microbes. If they 
can kill these mischief-makers as fast as they drift in, 
the wound will heal quickly ; if, instead, the phagocyte is 
too weak to slay the enemy, there will be a painful sore, 
slow to heal. Hospitals are full of patients who prove 
this difference in their own bodies. One man has a 


wound that heals at once, and he goes home happy; 
another man stays in the hospital for weeks, waiting 
for his wound to heal. The difference in the time of 
recovery rests with the phagocytes of the two men. 

What Pus Is. Matter, or pus, from a wound is the 
host of microbes and phagocytes that have been slain 
in the struggle. They are being washed away by fluids 
from the wound. It has been estimated that in one 
ounce of pus there may be as many as 150,000,000 
phagocytes who died fighting. 

The warfare within our bodies is a silent one; we 
hear no sound of any conflict. Nevertheless, throughout 
our lives the strife goes on ceaselessly, and it makes 
all the difference between life and death to us whether 
or not our standing army of phagocytes is in good 
fighting trim. 

In view of this fact our daily command to ourselves 
should be : Protect the phagocytes from harm. Many 
laws of health are, indeed, so truly laws for their protec- 
tion that he who follows these laws most strictly will at 
the same time be doing the most for his bodyguard. 

Cholera Epidemic and Alcohol. In Glasgow, in 1848, 
a little more knowledge might have saved hundreds of 
lives. A great cholera epidemic swept through the city, 
and it attracted so much attention that Dr. Adams 
studied it for the sake of telling people how to pro- 
tect themselves. He kept a keen eye on the death 


rate of his cholera patients and discovered that those 
who went without alcohol had a vastly better chance of 
recovery than those who used it. Or, to put the facts 
more exactly, when those who used alcohol caught the 
disease, ninety-one out of every hundred died; whereas, 
when those who did not use alcohol had the cholera, 
only nineteen out of every hundred died. 

Knowing what we do about the effect of alcohol on 
living tissue, and knowing also about the discoveries 
which Professor Metchnikoff made in connection with 
cholera microbes and phagocytes, we understand at 
once why that condition of affairs existed in Glasgow. 
The men and women who did not use alcohol owned 
phagocytes that were vigorous enough to conquer the 
attacking cholera microbes; the men and women who 
used alcohol had weakened their phagocytes to such an 
extent that when invading enemies came they were not 
strong enough to slay them. 

Dr. Delearde had two cases which illustrate precisely 
this point. 

Hydrophobia and Alcohol. A man and a boy were 
bitten on the same day by the same mad dog. The boy, 
thirteen years old, was bitten on the head and face, 
which are the very worst places for such wounds. The 
man was bitten on the hand alone — a much less serious 
matter. Both victims were taken to Dr. Delearde, and 
he gave each his most careful treatment; but the man. 


who should have recovered, died of hydrophobia, and 
the boy, who might have been expected to die, recovered. 
The only difference in the two cases seemed to be that 
the man used alcohol and the boy did not. 

Alcohol and the Phagocyte. This led Dr. Delearde to 
make experiments to determine whether or not alcohol 
had any effect on the phagocytes. He took two sets of 
rabbits ; to one set he gave a little alcohol each day ; the 
other set received no alcohol. He then vaccinated both 
sets as a protection against hydrophobia. After they were 
supposed to be proof against the disease, he put the 
poison of hydrophobia into their blood, and the experi- 
ment gave the result he had expected. The rabbits that 
had had alcohol took the disease as easily as if they had 
not been protected against it, whereas the poison had 
no effect whatever on the rabbits that had not had alco- 
hol. They did not take hydrophobia. Evidently their 
phagocytes had served them well. 

In looking back to the seventeenth chapter of Health 
and Safety, we now understand one reason why Bum and 
Tipsy suffered so much more than Nig and Topsy when 
the epidemic of dog illness raged in Worcester. Alcohol 
had weakened their phagocytes to such an extent that 
disease microbes had the upper hand from the start. 

Just here it is necessary to call attention to an impor- 
tant fact. When death comes from disease microbes, 
it is not the microbe itself but the poison which the 


microbe gives off while it multiplies that does the mis- 
chief. Each disease microbe has its own special variety 
of poison (toxin), and fevers of one sort or another 
simply show that a fierce fight is going on between 
microbes that are producing poison and phagocytes that 
are devouring the poison producers. 

Over and over again, in many microbe diseases, death 
comes from the fact that the body is poisoned by the 
toxin which the microbes have produced. 

Phagocytes that Multiply for Emergencies. This is par- 
ticularly true in that dread disease, pneumonia, and 
sometimes a doctor helps science by following the record 
of the battle. From time to time he draws a drop of 
blood from the arm of his patient and examines it under 
the microscope for phagocytes. He knows that the suf- 
ferers chance of life increases or decreases with the 
number of these protectors. The normal count is from 
5000 to 7000 phagocytes in each cubic millimeter, and 
it takes 50 cubic millimeters to make one drop of 

When, by his examination of the blood, the doctor 
finds that the number of phagocytes is mounting steadily 
upward from 10,000 to 20,000, from 20,000 to 50,000, 
and even to 70,000, he takes courage. He knows that 
" the body is rallying its forces to battle with the invad- 
ing hosts of microbes, and that if the fight can be kept 
up long enough, the victory will be won." 


Scientists say that phagocytes are being manufac- 
tured constantly in certain lymph tissues, and that when 
a special need comes, when a wound is made in the flesh 
or when disease microbes* multiply in the blood, then the 
tissues send out new regiments of phagocyte soldiers by 
the thousand and the million. And it seems that even 
the youngest of these soldiers is ready for immediate 

The Conqueror of the Phagocyte. Nevertheless, although 
a young and healthy phagocyte may be so vigorous as 
to be like a Samson among his microbe enemies, still, as 
we have seen already, there is a way to defeat and destroy 
him. Let one of these young phagocytes be launched 
into blood that has alcohol in it, and what is the result ? 
Does he gain courage for the fray? Does he hurry off 
to the battle ground with the greater strength? 

Quite the contrary; his fate is now sealed, for the 
alcohol overcomes him with a subtle power more deadly 
than that of any microbe. It is a poison which will dull 
a phagocyte or paralyze him utterly, according as there 
is more or less of it in the blood. 

A trace of alcohol does not rob phagocytes of all 
power. They may still be strong enough to reach the 
scene of battle ; they may even contend with a microbe 
on the way there; but instead of being strong enough 
to conquer, they are now weak enough to be conquered. 
When such a condition exists, disease microbes find 


themselves free to carry on their business of toxin 
manufax:ture without interruption. 

From beer and hard cider all the way through to gin 
and brandy, every drink containing alcohol harms the 
phagocyte, and the more alcohol the drink holds the 
more is the phagocyte damaged by it. The following 
table shows what per cent of alcohol is found in various 
drinks that are in common use: 


Beer 3-5 

Hard cider 4-5 

Ale 7-8 

Wines of different kinds 7-20 

Champagnes 11-18 

Brandy 30-55 

Whisky 50 

The Man who Drinks. In view of this power of alcohol, 
we realize that when a man raises his glass cheerfully 
to his lips and drinks to the health of his king or 
his friend, he drinks in truth to the success of disease 
microbes in his own body, while at the same time he 
drinks to the death of his own most faithful bodyguard. 

If the owner of a castle had drugged his watchmen 
on the towers, had bound his soldiers hand and foot, and 
had killed his bodyguard, would he have the right to 
be surprised when he found his worst enemy within the 
gates? If that enemy robbed him, or beat him cruelly, 


or killed him by slow torture, would any one be to 
blame but the owner of the castle himself? 

Protect your phagocytes from harm by observing the 
laws of health, and they will protect you in time of need. 
Weaken them through the use of alcohol or any other 
poison, or through neglect of the laws of health, and 
you will be as a man who has drugged his watchmen 
on the towers, bound his soldiers hand and foot, and 
killed his bodyguard. He who has done all this is 
sure to suffer when the enemy comes. 


1. What is the phagocyte ? 2. What does its name mean ? 

3. Describe the experiment with the frog and the cholera microbes. 

4. How do phagocytes capture and destroy microbes? 6. Why does 
a frog never die of cholera? 6. Why do pigeons never have tuber- 
culosis? 7. Describe the action of phagocytes in the body. 8. If in- 
truding disease microbes are more numerous or more vigorous than our 
phagocytes, what happens to us? 9. If a person yields quickly to a 
disease, what does this prove about his phagocytes ? 10. If he is able 
to resist disease, what is it that has saved him ? 11. What does the 
phagocyte do in case we are cut or wounded ? 12. What is pus ? 
13. What difference may there be in the healing of the wounds of 
two men in a hospital? 

14. What should be our daily command about phagocytes ? 15. What 
connection is there between the laws of health and the vigor of the 
phagocyte ? 16. What was noticed during the cholera epidemic in Glas- 
gow in 1848 ? 17. How do you explain the connection between the 
death rate and the drinking of alcohol? 18. Tell about the boy and 
the man who were bitten by the mad dog. 19. What experiments did 


Dr. Delearde make on the rabbits ? 20. How did he explain the 
results? 21. Why did Bum and Tipsy suffer more from disease than 
Nig and Topsy ? 22. Which does the most harm in the body, disease 
microbes themselves or the toxin they produce? 23. In a case of 
pneumonia, why does the doctor take courage when phagocytes in- 
crease their numbers ? 24. Where does he look for the phagocytes ? 
25. What occurs when a phagocyte finds itself in blood that holds 
a trace of alcohol? 26. When phagocytes are overcome by alcohol, 
what is the outlook for disease microbes in that body? 27. When a 
man drinks to the health of his friend, to whose success and to whose 
death is he really drinking ? 28. Why should we protect the phagocytes 
from harm ? 


Allen, W. H. Civics and Health. 

Cannon, W. B. The Movements of the Stomach studied by Means of the 

Rontgen Rays. American Journal of Physiology ^Nf:\, I. 
Cannon, W. B. The Movements of the Intestines studied by Means of the 

Rontgen Rays. American Journal of Physiology^ Vol. VI. 
Chittenden, R. H. The Nutrition of Man. 1907. 
De Forest, Robert W., and Veiller, Lawrence. The Tenement House 

Problem. 1903. 
GoLER, George W. The Influence of the Municipal Milk Supply upon the 

Deaths of Young Children. 1903. 
GuLiCK, L. H. Physical Education by Muscular Exercise. 1904. 
GuLiCK, L. H. The Efficient Life. 1907. 
Harvey, William. Anatomical Disquisition on the Motion of the Heart 

and Blood in Animals. Written in 1628, Translated from the Latin by 

Robert Willis. 
HoRSLEY, Sir Victor, and Sturge, Mary D. Alcohol and the Human 

Body. 1907. 
Hough, Theodore, and Sedgwick, W. T. The Human Mechanism. 1906. 
Howard, L. O. Mosquitoes: How they Live; How they Carry Disease; 

How they are Classified; How they may be Destroyed. 1902. 
Howell, W. H. A Text-Book of Physiology for Medical Students and Physi- 
cians. 1907. 
James, William. The Principles of Psychology. 1893. (Chapters on Habit, 

Will, Memory, Attention.) 
Jewett, Frances Gulick. The Next Generation. 191 4. 
Jewett, Frances Gulick. Town and City. 1906. 
Jewett, Frances Gulick. Control of Body and Mind. 1908. 
McKeever, Wm. a. The Cigarette Smoking Boy. 1909. 
Sargent, Dudley A. Health, Strength, and Power. 1904. 
Schmidt, Ferdinand August. Unser Korper. 1903. 
Seaver, J. W. Effects of Nicotine. The Arena, Vol. XVH. 
Stiles, C. W. Hookworm Disease. 1910. 




a as in fate, senate, f&t, &rm, %\\, tisk, what, c&re. 









mgte, ^vent, m6t, hgr, th§re, they. 


Ice, idea, It, sir, machine. 

Old, 6bey, not, move, W9lf, son, h6rse, work. 

food, foot. 

use, 4nite, up, ffir, r\}Ie, p^ll. 

fly, mjrself, baby, myrrh. 


saw. ew 

boy. ou 

c (unmarked) as in call ; 5 
ch (unmarked) " child ; qh. 
g (unmarked) " go; g (=j) 
ng as in ring. n (=ng) 

g(=z) " is. si(=sh) 

th (unmarked) as in thin ; tii 
X (unmarked) " vex; J (=gz) 
Obscure sounds : ^, g, i, etc. Silent letters are italicized. 

\ in new. 


as in boil. 

" out. 


" cow. 

" mice. 

ci (=sh) 

" gracious. 

*' chaise ; 


*' school. 

" cage. 

" ink. 


as in phantom. 

" tension ; 

§i ( = 2h) 

" vision. 

»' then. 

ti (=sh) 

" motion. 

'* exact. 

abdo'mgn, the part of the body 
below the diaphragm. 

Sd'e noid, a growth of tissue in the 
back of the nose. 

a dtil'ter ate, to make impure. 

allmgn'tary canal, the food 

an Sph'e leg, a species of mos- 
quitoes that carry malaria. 

antlsgp'tlc, anything which de- 
stroys the microorganisms of 

an tl tSxIn, a substance which neu- 
tralizes the action of a toxin or 

anVll, one of the small bones of 
the ear. 

a or'ta, the great artery from the 

a'pSx, the top or summit of any- 

a'qu^ ous hii'mor, the liquid be- 
tween the crystalHne lens and 
the corona of the eye. 



ar'chl t6ct,onewho plans buildings. 

ar te'rl al, pertaining to the arteries. 

ar'ter f, one of the vessels or tubes 
which carry the blood from the 

as tig'ma tlgm, a defect in the re- 
fractive apparatus of the eye. 

at'r6 phy, a wasting away from lack 
of nourishment 

au'dl t6 I'y, pertaining to the outer 
and inner passages of the ear. 

au'rl cle, a division of the heart re- 
ceiving blood from the body. 

au'to-In t6x I ca'tion, poisoning of 
the body by toxins formed within 
the body. 

ax 'on, a fiber from the cell body. 

baQll7iis, a microbe which is the 

■ cause of various diseases, 
bac te'rl a, forms of microbes. 
b6v'er, drink of any kind, 
bi'qgps, a muscle having two heads ; 

the term is applied to a muscle 

in the arm. 
bile, a yellow, bitter fluid, secreted 

by the liver. 
bi§'m1ith subnitrate, a chemical 
brSn'chl al, belonging to the tubes 

or air passages of the lungs. 
brSn'chl ole, a small bronchial tube. 

eafy^Ine, an alkaloid found in 

caplZ li rj-, one of the tubes con- 
necting arteries and veins. 
car'b6 hy'drate, a chemical term. 
carT^Sn dl Ox'Ide, carbonic acid ; a 

car'dl ac, pertaining to the heart, 
car'tl, an elastic tissue; gristle. 
e6l7il lose, the inclosing membrane 

of plant cells, 
^r $ bel'Ziim, a division of the brain 

situated at the back of the head 

below the cerebrum. 
Q6r'$brtlm, the upper and larger 

division of the brain. 
ehSl'era, an infectious and often 

fatal disease of the digestive 

chyle, the contents of the small 

chyme, food in the form in which 

it passes out of the stomach. 
Qllla, minute hairlike growths 

from a cell or other part or 

organ of the body. 
Qir cti la'tion, motion in a circle or 

Qir'cft la t6 ry, pertaining to circu- 
lation, as of the blood. 
CO ag ti la'tion, the act of changing 

from a fluid to a thickened state, 
co'calne, a drug which produces 

local insensibility. 
coch'lSa, a part of the inner ear 

in most vertebrate animals. 




c6n'cave, curved in. 

c6n trac'tion, a shrinking; shorten- 

cor'n^ a, the hard transparent front 
portion of the eyeball. 

cor'ptis cle, a minute particle ; blood 
corpuscles — the blood disks or 

e6r't6x, the layer of gray matter 
covering the surface of the brain. 

cr\^de, raw, not fitted for use by 
any artificial process. 

cr^s'tal line leng, a lens of high 
refracting power behind the iris 
of the eye. 

cti'lgx, the common, harmless mos- 

curVa tuie, a bend ; a curve. 

Czar'e vl^ch, the title applied to the 
eldest son of the emperor of 

dfin'drite, a crooked fiber from the 

cell body, 
der'mls, the second layer of skin, 
di'aphra^m, a muscle separating 

the chest from the abdomen, 
dlph the'rl a,adiseaseof the throat, 
dis In fgc'tion, destruction of the 

germs of contagious diseases. 

6pld6m1c, a disease attacking 
many persons at the same time. 

6pl der'mls, the outer layer of 

6plgl6t'^ls, a valvelike organ 
which keeps food and drink from 
getting into the larynx. 

6 rtip'tlve disease, a type of disease 
affecting the skin. 

6r f sip's las, a disease character- 
ized by an inflammation of the 
skin and accompanied by fever. 

JSti sta'chl an tube, a tube leading 
from the middle ear to the 

6x pgc'to rate, to spit. 

6x tgn'sor, a muscle which extends 
or straightens any part of the 

flgx'or, a muscle which bends any 
parf of the body. 

gan'gll 6n (plural, ganglia), a col- 
lection of nerve cells. 

gas 'trie juice, a fluid secreted by 
the stomach. 

ggl'a tin, a substance made by boil- 
ing bones and other tissues. 

germ, microbe. 

gland, a secretory part or organ, 
which secretes a substance pecu- 
liar to itself. 

glSb'ule, a little globe. 

glSt'^ls, the mouth of the windpipe. 

gly'co g6n, a substance found in 
many animal tissues and espe- 
cially abundant in the liver. 


goi'ter, enlargement of the thyroid 
gland on the front and sides of 
the neck. 

grto'ule, a little grain, a fine particle. 

g^m'nSst, one skilled in athletic 

ham'mer, one of the small bones 

of the middle ear, named from 

its shape, 
hi'ber nate, to pass the winter in a 

torpid state, as some animals do. 
hy dr6 chlo'rlc acid, an acid formed 

by the union of chlorine and 

hy dr6 pho'bl a, a disease caused 

by the bite of a mad dog. 

In flvi. 6n'za, an epidemic catarrh. 
Ingred'Ient, one of the elements 

of a combination, as a drink or 

In 6c 'ft late, to introduce germs into 

the tissues for protection. 
In ter cSs'tal, between the ribs. 
In tgs'tlne, the lower part of the 

alimentary canal, 
i'rls, the colored curtain of the eye, 

seen in the front of the eyeball. 

lab'y rinth, part of the inner ear. 
lach'rymal gland, a gland which 

secretes tears, 
lar'ynx, the part of the windpipe 

in which vocal soimd is made. 

lat'er al, sidewise. 

league, persons united for some 
particular purpose. 

llg'a ment, the tissue that connects 

lymph, a colorless fluid found in 
animal bodies. 

lym phat'Ic, a vessel which con- 
veys lymph. 

mar'rOM?, a soft tissue found in the 

interior of the bones. 
m6a'gle§, an eruptive contagious 

mgm'brane, a thin soft tissue in 

the form of a sheet or layer 

covering parts of the body. 
m6n'u,. a bill of fare, 
mi'crobe, a creature so small that 

it can be seen only through a 

Ml cro ne'sla, a collection of islands 

and groups of islands in the 

Pacific Ocean, 
mi'cro scope, an instrument for 

examining objects too small to 

be seen by the naked eye. 
mu'eus, a thick fluid secreted by 

the mucous membrane of ani- 
mtis'cle, a tissue the contraction of 

which causes motion, 
mtts'cftl^r, having well-developed 

muscles; strong. 



narcSt'Ic, a substance having the 
power to produce stupor. 

neti'rSn, a nerve cell. 

nlc'6 tine, a highly poisonous sub- 
stance obtained from tobacco. 

ni trSg'e nous, pertaining to nitro- 

nSr'mal, regular ; natural. 

nu'cl^ us, the vital center of a cell. 

nutrl'tion, that which nourishes 
or repairs the waste in tissues. 

oesophagus ($ sof ^ g^s), the tube 
through which food and drink 
are carried to the stomach, 

61 fac'to rj^ nerve, the nerve con- 
nected with the sense of smell. 

o'pl tim, the dried juice of the 
poppy; a drug. 

6p'tlc nerve, the nerve connected 
with the sense of sight. 

6r'gan1c, pertaining to objects that 
have organs; hence pertaining 
to the animal and vegetable 

5s mo 'sis, the diffusion of- fluids 
through animal membranes. 

6x 1 da'tion, the process of com- 
bining with oxygen. 

Sx'ygen, the element of the air 
that supports animal life. 

pal'ate, the roof of the mouth and 
floor of the nose. 

pan'crSas, a gland near the 
stomach which secretes a fluid 
having important uses in diges- 

pancreatic fluid, a clear liquid 
secreted by the pancreas. 

par 'a lyze, to render helpless. 

Pas'teiir Institute, a place where 
Pasteur^s method of treating 
certain diseases is practiced. 

pat'ent m6d'i Qlne, a ready-made 
medicine, sometimes patented. 

p6r 1 6s 't$ um, a fibrous membrane 
covering the surface of bones. 

pSr I stal'tic, contracting in suc- 
cessive circles. 

phag'6 qy te, a white blood corpuscle. 

phar'ynx, the part of the food canal 
between the mouth and the 
oesophagus. . 

plg'mgnt, coloring matter. 

pla§'ma, the liquid part of the 

pleu'r^, the membrane which lines 
the walls of the chest. 

pleti'rlsj-, inflammation of the 

plgx'us, a network of nerves. 

pneumo'nla, inflammation of the 
tissues of the lungs. 

Po'nape, one of the Caroline 

pro'te Id, a substance from which 
living tissue is formed. 


pro't6 pla§m, a substance consti- 
tuting the basis of life of all 
plants and animals. 

^tom^'ln^, a substance formed 
from animal or vegetable tissues 
during putrefaction. 

ptH'mdnirJ-, pertaining to the 

ptQse, the beating of the heart as 
felt in the arteries. 

ptis, an inflammatory liquid issuing 
from abscesses or sores. 

-pf iSr'Ic, pertaining to the pylorus. 

py'lo'rus, the opening through 
which the contents of the 
stomach pass into the intestine. 

r6g I mgn'tals, military clothing. 

rAJth'mlc, occurring at regular in- 
tervals, like accents in poetry or 

rick'gts, a disease of children, in 
which they are weak in the 

ro'tate, to revolve ; to move round 
a center. 

sal I ^I'lc, the name of an acid. 

sa li'va, a digestive fluid secreted by 
glands in the mouth. 

sail va ry, pertaining to saliva. 

sanlta'tion, putting and keeping 
anything in healthy condition. 

sar c6 iSm'ma, the covering of sep- 
arate muscle fibers. 

scl6 rSflc coat, part of the eyeball 

sew'age, the matter which passes 
through sewers. 

sk6l'6 tal, pertaining to a skeleton, 

sphyg'm6 graph, an instrument 
used in determining the strength 
of the heart beat. 

spti'ttlm, that which is spit or raised 
from the lungs. 

st6g 6 myi a, a mosquito that car- 
ries yellow fever. 

stlm'ft lant, that which excites. 

stir'rup, one of the three bones of 
the middle ear. 

stom'ach, part of the digestive 

sym mgt'rlc al, well proportioned 
in its parts. 

s^no'vlal fluid, secreted in the 

syringe, an instrument like a 
pump, for drawing in and eject- 
ing liquids. 

sys t6m1c, pertaining to the body 
as a whole. 

tad'pOle, the young of a frog. 

t6n'd6n, a bundle of fibers which 
joins a muscle to a bone. 

tfinsely, tightly ; rigidly, 

thelna, a substance found in tea. 

the 6 bro'mlne, an alkaloid sub- 
stance found in chocolate and 
in cocoa. 



tho ra^'Ic, pertaining to the thorax, 

or chest, 
thy'roid, a gland in the neck. 
t6n'sll, one of two oval bodies on 

each side of the opening of the 

t6x'In, a poison produced in the 

tra'chS a, the windpipe, beginning 

at the larynx and ending at the 

bronchial tubes, 
tra eho'ma, a disease of the eyes, 
tu ber cle, a small mass of diseased 

tu ber cti lo'sis, a disease caused by 

the tubercle bacillus, 
ty'phoid, a disease caused by con- 
taminated food or drink, 
ty'phus, a kind of fever. 

vSc qI nSi'tidn, inoculation with vac- 
cine to prevent smallpox. 

va'por iz6, to convert a liquid into 

vein, a vessel which receives blood 
from the capillaries and returns 
it to the heart. 

vg'nous, pertaining to the veins. 

v6n'trl cle, a division of the heart 
receiving blood from the auricle. 

ver't^ bra, one of the small bones 
which make up the spine. 

vI17iis (plural, vil7i), a minute ele- 
vation on the lining of the small 

vlt're ous hti'mor, the transparent 
jelly which fills the back part of 
the eyeball. 

v6l'a til ize, to cause to evaporate. 


Aschaffenburg (a sha'f en boork) 

De bove' 

De le arde' 

Fti §ans' 

Flourens (floo rans') 

^6 t6l de YiW 

Krae'pe Im 
M&tch'nl koff 
Pavlov (paviaf) 


Adams, Dr., 343 

Adenoids, 114 
treatment for, 115 

Air, need that it be fresh, 303-305 
need of moisture in, 118 

Air sac, description of, 117 
gas exchanges through, no 
location of, 109 
muscular wall of, 28 
when inactive, in, 112 

Alcohol, curtailing sale of, in England, 
effect of, on the heart, 97, 98, 100 
effect of, on the phagocyte, 345 
effect of, on soldiers, 262 
effect of, on taxes, crime, and poverty, 

191, 192 
effect of, on typesetters, 261, 262 
French attitude towards, 186 
German attitude towards, 187 
legislation about, in Japan, 189 
movement against, in the United 

States, 189 
percentage of, in common drinks, 348 
prohibition of, in Newfoundland, 191 
prohibition of, in Russia, 188 
relation of, to efficiency, 260-265 
relation of, to heart beat, 96 
relation of, to hydrophobia, 344 

Alimentary canal, description of, 146 

Anderson, Dr., 122 

Animals, cold-blooded, 203 
warm-blooded, 203 

Anopheles, a mosquito, 329 

Antiseptics, value of, 335 

Anvil, bone in the ear, 249 

Arteries, location of, 58, 60 
what they are for, 57, 58 

Aqueous humor, part of the eye, 246 

Aschaffenburg, Dr., 261, 262 

Auditory canal, part of the ear, 248 

Auricle, 61, 63 

Australians, trained sight of, 239 

Auto-intoxication, 174 

prevention of, 175, 176 
Axon, part of the neuron, 226 

Back, reasons for its shape, 13, 14 

Bacteria, 268 

Biceps, exercise for, 17 

tendons of, 23 
Bile, a digestive fluid, 155 

where manufactured, 169 
Bismuth, use of in experiments, 141 
Blood, in the arteries, 88 

carrier of oxygen, 105 

changed while in the lungs, 109 

examining a drop of, 82 

exchange of gases in, 87 

flow of, 60 

individual supply of, 70 

under the microscope, 83 

in the veins, 89 

what it does, 85 
Body cavities, 180 
Body temperature, 207, 208 

regulation of, 202 
Bones, chemical composition of, 32 

in the ear, 249 

effect of work on, 36 

of the foot, 40 

the framework of the body, 30-46 

how held together, 35 

number of, 34 

records of, 4 

shape and size of, 33 

structure of, 30 

tuberculosis of, 296 

young and old, 33 
Brain, aided by the sympathetic gangliat 

center of the senses, 242 



Brain, gray and white substances of, 
219, 220-231 

structure of, 217 
Breathlessness, avoidance of, 107 

cause of, 105, 106 

description of, 103 
Bridgman, Laura, 243 
Bronchial tubes, description of, 117 
Bronchioles, description of, 117 
Brotherhood of Locomotive Engineers, 

Caffeine, a poison, 165 
Candy, why objectionable, 165 
Cannon, Dr., 138, 150, 255 
Capillaries, connections of, 64 

definition of, 68 

in the liver, 171 

relation of, to air sacs, no 

relation of, to warmth, 98 
Carbohydrate, definition of, 124 

as energy producer, 127 
Carbon dioxide, effect of, on the color 
of blood, 109 

exchange of, for oxygen, 118 

in the lungs, no 

when produced, 105 
Cardiac muscle, location of, 141 

ofiice of, 147 
Carpenter, Dr., 240 
Cartilage, between vertebrae, 35 

defined, 116 (footnote) 

in young bodies, 3 
Cats, food experiments with, 138-144 
Cell body, part of neuron, 226 

as telegraph center, 228 
Cellulose, an envelope, 127 

softened by cooking, 163 
Cerebellum, as aid to the cerebrum, 233 

location of, 218 

training of, 233-250 

work of, 233 
Cerebrum, appearance of, 218 

centers in, 220 

location of, 217 

and memory, 216 
China, small feet in, 38, 39 
Chittenden, Professor, 121, 131 
Chocolate as a drink, 164 
Cholera and alcohol, 343, 344 

Choroid coat of the eye, 246 

Chyle, relation of, to the villi, 151, 158 

where found, 147, 149 
Chyme, a condition of food, 143 

preparation of, 147 
Cigarettes, effect of, on heart, 80 
Cilia, location of, 117 
Circulation, Harvey's discovery of, 64 

when slow, 95 
Circulatory system, description of, 65 
Clothes, why needed, 204 
Coagulation, description of, 83 
Cochlea, part of the ear, 249 
Cocoa, objectionable feature of, 164 
Coffee, why harmful, 165 
Cold, how to check a, 201 

rules of prevention for a, 201, 202 

symptoms of a, 200 

taking, 199 
Colon, location of, 148 
Connective tissue, 22 
Consumption not heritable, 297 
Cornea, description of, 246 
Corpuscles, in capillaries, (i^ 

description of red, 84 

description of white, 85 
Cortex, cell bodies in, 227 

how developed, 244 

of Laura Bridgman's brain, 244 

name of gray layer, 221 
Crystalline lens, part of the eye, 246 
Culex, a mosquito, 329 
Curvature of spine, 9 

prevention of, 10 

Debove, Professor, 186 
Delearde, Dr., 345 
Dendrite, part of neuron, 226 
Dermis, location of, 197 
Diaphragm, location of, 182, 183 

rhythmic movement of, 183 
Digestion, chemical fluids of, 154-156 

emotions which aid, 144 

emotions which hinder, 143 

and good temper, 255 

influenced by appetite, 162 

of milk, 160 

process of, 138-152 
Diphtheria, cause and prevention of, 



Disinfection, importance of, 335 
Donovan, "Mike," 81 
Dyes, danger from, 285 

Ear, hygiene of, 249 

structure of, 248, 249 
Eardrum, part of the ear, 248 
Eating, mistakes in, 1 58 

rules for, 130 
Edwards, Mr., football captain, 80 
Epidermis, value of, 197 
Epiglottis, 115 

Eustachian tube, location of, 249 
Excretion, organs of, 183 
Exercise, advantage of, to Ijrmph flow, 

effect of, on blood supply, 7 1 

value of, to health, 112 

warmth by means of, 205 

when to be avoided, 145 
Eyes, diseases of, 270, 271 

protection of, 270, 271 

structure of, 245, 246 

Facial expression controlled by neurons, 

Faisans, Dr., 186 

Fat, reduction of, 206 

stored in the body, 127 
Fatigue, effect of, on nerve cells, 230 

remedy for, 230 
Fisher, Professor, 305 
Flies, what they eat, 273 

why objectionable, 271 
Flourens, Dr., 233 
Food, for bulk, need of, 132 

canned, 286 

five substances of, 124 

as fuel, 205 

inspection of, 285 

laws for protection of, 285 

production of, by plants, 126 

study of cost of, 1 26 

waste, 152 

what it does for the body, 1 23 

why we cook it, 163 
Food tube and peristaltic action, 148, 

149, 150 
Foot, arch of, 41 

deformed by shoes, 41 

Foot, rules of hygiene for, 42 
under pressure, 38, 39 

Gall bladder, 169 
Ganglia, cell bodies in, 227 

deflnition of, 227 

influenced by happiness, 256 

location of, 254 

service from, 258 
Gastric glands, location and use oi^ 

I47» 15s 
Gastric juice, 155, 161 

Gelatin from bone, 32, 33 

Germs, meaning of, 268 

Glands, 177 

ductless, 177 

lachrymal, 177 

thyroid, 177 
Glottis, description of, 115 
Glycogen, 168 

manufacture of, interfered with, 178 

Hammer, bone of the ear, 249 
Happiness, and good digestion, 144 

why helpful, 256 
Harvey, Dr., his discovery, 56 
Headache, relation of, to auto-intoxica- 
tion, 176 
Health and Safety^ references to, 109, 

113, 117, 118, 130, 135, 164, 345 
Heart, action of, influenced by happi- 
ness, 256 

development of, 56 

effect of exercise on, 50 

how weakened, 10 1 

muscles of, 52 

overstretching, 54 

overtaxing, 52 

size of, 55 

structure of, 62 

training, 53, 54 

work of, 58 
Heart beat tested, 50 
Heidelberg University, 260 
Hodge, Dr., 230 
Hookworm disease, 329-332 
Howell, Dr., 216 

Hydrochloric acid in the stomach, 155 
Hydrophobia, and alcohol, 344 

cause and prevention of, 327 


Indians, flat heads secured by, 4 
Intestinal juice, digestive fluid, 1 56 
Iris, part of the eye, 246 

Jenner, Dr., 325 

Joints, ball-and-socket, 44 

hinge, 43 

their location, 42, 43 

Kidneys, 172 

effects of alcohol on, 173 

relation on, of proteid, 1 29 
Koch, Dr. Robert, 289 
Kraepelin, Professor, 260 

Labyrinth, part of the ear, 249 

Lachrymal gland, 245 

Lacing, harm of, 178 

Large intestine, description of, 148 

Larynx, description of, 116 

Lieutenant Rengt Boy, 262 

Ligaments in foot and ankle, 40 

illustration of, 38 
Liver, effects of alcohol on, 170 

effects of lacing on, 178 

what it is and what it does, 1 68-1 71 
London, overcrowding in, 282 
Lord, Dr., 273 

•* Lung Block," death rate in, 292 
Lungs, action of, influenced by happi- 
ness, 256 

clean air for, 117 

effect of lacing on, 180 

expansion of, 108 

relation of, to blood, 109 

structure of, 108 

trained and untrained, 108 

work of, 109 
Lymph, composition of, 89 

description of, 91 
Lymphatic system, description of, 89-93 
Lymphatics in the hand, 91 

McBride, Mr., 80 

McKeever, Dr., 73 

Malaria, cause and prevention of, 328, 

Marrow, 34 

Marshall Field and Company, 190 

Mayer, Dr., 9 

Measles, cause and prevention of, 323, 

Memory, as related to the cerebrum, 

216, 217 

Menus, balanced, 131, 133 

Mernetsch, Dr., 264 

Metchnikoff, Professor, 338, 339, 340, 

Microbes, danger of, from public towel, 


deaths caused by, in war, 272 

definition of, 26S 

• effect of cooking on, 164 

how they attack us, 269 

of influenza, 341 

in the intestine, 174, 175 

menace of, 267-277 

and the phagocyte, 338 

and the public drinking cup, 267 

safety from, 322-336 

on sand filters, 312 (footnote) 

of typhoid fever, 309 

typhoid, in milk, 316 

the way they damage teeth, 134 

when we take cold, 200 
Milk, causes of impurity of, 319 

conditions of cleanliness, 317 

conditions of uncleanliness, 318 

how made safe, 319 

and microbes, 316 
Mineral food, where found, 129 
Mosquitoes, relation of, to disease, 328^ 

Mouth, description of, 146 

Mumps, 333 

Muscles, antagonistic, 18 

in bent back, 13 

developed without apparatus, 19 

development of, 17 

effect of work on, 14, 15 

of the eye, 245 

fibers of, 21, 24 

flexor and extensor, 18, 19 

how shaped, 17 

to increase size of, 20 

intercostal, 29 

involuntary, 28 

the law of their contracting and 
stretching, 16 

records made by, 4 



Muscles, shapes of, 21 
skeletal, 26 
structure of, 20, 21 
toughness of, 25, 26 
voluntary, 26 
weight of, 28 

Narcotic, definition of, 98 (footnote) 
Nasal duct, 245 

Nerve fibers, affected by spinal curves, 

appearance of, 212, 213 

bundles of, 222, 223 

different sets of, 213 

endings of, 222 

from ganglia, 254 

length of, 214 
Nerves, 212 

when cut across, 224 

distribution of, 215 

kinds of messages carried by, 224 

machinery of, 221 
Nervous system under command of 

the cerebrum, 233 
Neurons, and alcohol, 265 

in the cerebellum, 234 

and facial expression, 237 

four facts about, 238 

how to train them, 235 

results of training, 236 

structure of, 225-227 
Nicotine, effect of, on the heart, 78 

how it gets to the heart, 78 

and the sphygmograph, 73 
Nucleus of cell body, 226 

CEsophagus, description of, 146 

Olfactory nerve, 250 

Optic nerve, endings of, on the retina, 

Osmosis, law of, 87 

Oxygen, demand of fibers for, 105 
part of the air, 118 
relation of, in the blood, no 

Palate, location of, 114 
Pancreatic fluid for digestion, 156 
Parks and playgrounds, 283 
Pasteur Institute, 338 
Patent medicine, objections to, 287 
Pavlov, Professor, 159, 162 

Pepsin, 155 

Periosteum, definition of, 30 

Peristaltic action, importance of, 148 

object of, 157 
Perspiration, 197, 199 

cooling device, 205 

insensible, 199 

manufacture of, 196 

sensible, 199 
Phagoc)rte, and alcohol, 345 

the conqueror of, 347 

description of, 338 

man's defender, 338 

method of work, 339 

and pneumonia, 346 

as scavenger, 342 
Pink eye, contagion of, 335 
Pittsburgh, former conditions in, 308 

change in its death rate, 311 
Plasma, part of the blood, 84, 91 
Pleura, definition of, 117 
Pleinisy, 117 
Plexus, definition of, 254 
Pneumonia, and the phagocyte, 346 

prevalence and prevention of, 334 
Poole, Mr. Ernest, 293 
Proteid, 124 

digestion of, 161 

use of, 129 

where found, 128 
Pulse, action of, 48, 49 

relation of, to heart beat, 49 
Pupil, part of the eye, 246 
Pure-food laws in the United States, 285 
Pus, 343 

Pylorus, behavior of, during digestion, 

service of, to the stomach, 147 

work of, 141, 142 

Rear tenements and the death rate, 282 

Rennin in digestion, 155 

Retina, part of the eye, 246 

Riis, Mr., 323 

Rochester and clean milk, 320 

Safety through carefulness, 274, 275 
Saliva, effect of, on carbohydrate, 160 

flow of, through desire, 159 

what it does, 1 54 


Salivary glands, affected by chewing, i6o 

number of, 1 59 
Sand filters, safety by use of, 311 
Sanitation, in city surroundings, 277 

contrasts in country and city, 279 

conditions of, in country, 277 

meaning of, 278, 279 
Sarcolemma, 22 
Scarlet fever, cause and prevention of, 

Schmidt, Dr., 9 

Sclerotic coat, 246 

Seaver, Dr., 79 

Secretion, defined, 184 

from glands, 162, 177 
Sensations, significance of, 211 
Sense centers, enlargement of, 243 
Senses, machinery of, 242 

their training, 238, 239 
Sepala, Professor Helenius, 188 
Sewage, disposal of, in country and 

city, 279 
Sewage system, study of, 284, 285 
Skin, effect of heat on, 195, 196 

structure of, 197 

what it does, 198, 199 
Skull, protection for the cortex, 221 
Small intestine, 147 

effect of lacing on, 179 
Smallpox, 324 

vaccination for, 325 
Smell, sense of, 250 
Smoking, effect of, on heart, 75, ^(i 

general effects of, 74 
Soldiers, experiments with alcohol, 262 

in eating experiments, 121, 122 
Sparrow, effect of fatigue on brain cells 

of, 230 
Sphygmograph, use of, to show heart 
beat after alcohol, 97 

description of, 73 

records made by, 76, Tj 
Spine, 9, 34, 35 

Spinal cord, cell bodies in, 227 
Spinal nerves, relation of, to backbone, 

Spine, when twisted, 8 
Sputum, air contaminated by, 299, 300 

danger from, 296 

disposal of, 302 

Stagg, Mr., 80 
Starch. See Carbohydrate 
Stegomyia, a mosquito, 328 
Stimulant, defined, 98 (footnote) 
Stimuli, carried by nerves, 212, 214 

relation of, to sense apparatus, 244 
Stirrup, bone in the ear, 249 
Stomach, action of, during digestion, 

effect of lacing on, 179 

influenced by happiness, 256 

relation of, to alimentary canal, 147 
Sweat glands, a cooling device, 206 

numbers of, 196 

as protectors, 195, 196 
Sympathetic ganglia, work of, 252,. 

Sympathetic nervous system, 253, 254 

Synovial fluid, use of, 46 

Tadpole, corpuscles in tail of, 67 
Tea, why harmful, 165 
Teeth, care of, 135 

how damaged, 134 
Tendon, description of, 23, 24 

use of, 46 
Theine, a poison, 165 
Theobromine, a poison, 165 
Tobacco, effects of, 73-81 
Tobacco heart, 78 
Tonsils, work of, 114 
Touch, sense of, 250 
Trachea, description of, 117 
Trachoma, relation of, to public towel, 

Treves, Sir Frederick, loi 

Tubercle bacillus, description of, 290- 


how distributed and lodged, 294, 295 

our foe, 289 

in the lungs, 295 
Tuberculosis, of the bones, 296 

death rate from, 289, 292, 293 

discovery of its cause, 290 

not found among pigeons, 340 

fresh air in treatment of, 303-305 

rules for its prevention, 301, 302 

treatment of, 301 

war against, 297-299 
Tuberculosis '* D's," five, 302 



Typesetters, tests made with, 261, 262 
Typhoid microbes, in drinking-water, 

in milk, 316 

Vegetarians, belief of, 132 
Veins, location of, 58 

valves in, 59 

work of, 61, 63 
Vertebrae, relation of, to spinal nerves, 

wedge-shaped, 36 

what they form, 35 
Villi, description of, 148 

their number and structure, 1 56 

what they are, 1 57 

what they do, 151 
Vitreous humor, part of the eye, 246 

Vocal cords, location of, 116 
treatment of, 116 

Water, the body's need of, 130, 131 
how purified, 311, 312 
from lakes and wells, 313, 314 
the London supply of, 315 
sources of, for city supply, 315 
when contaminated, 308, 309 

Whooping cough, how to prevent its 
spreading, 333 

X ray, showing action of stomach, 143, 
for the study of digestive action, 

Yellow fever, 328, 329